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                                                                     EXHIBIT 3.2

                     AMENDMENT NO. 1 TO AMENDED AND RESTATED
                       AGREEMENT OF LIMITED PARTNERSHIP OF
                         NORTHERN BORDER PARTNERS, L.P.

      This Amendment No. 1 to Amended and Restated Agreement of Limited
Partnership of Northern Border Partners, L.P. (this "Amendment"), dated as of
April 6, 2006, is entered into and effectuated by Northern Plains Natural Gas
Company, LLC, a Delaware limited liability company ("Northern Plains"),
Northwest Border Pipeline Company, a Delaware corporation ("Northwest Border"),
and Pan Border Gas Company, LLC, a Delaware limited liability company ("Pan
Border" and, together with Northern Plains and Northwest Border, the "General
Partners"), as the General Partners, pursuant to authority granted in Section
4.2 and Section 15.1 of the Amended and Restated Agreement of Limited
Partnership of Northern Border Partners, L.P., dated as of October 1, 1993 (the
"Partnership Agreement"). Capitalized terms used but not defined herein are used
as defined in the Partnership Agreement.

                                RECITALS:

      WHEREAS, Section 4.2(a) of the Partnership Agreement provides that the
Partnership Policy Committee, without the approval of any Limited Partners, may
issue additional Partnership Securities, or classes or series thereof, for any
Partnership purpose, at any time or from time to time, and may issue such
Partnership Securities for such consideration and on such terms and conditions
as shall be established by the Partnership Policy Committee in its sole
discretion;

      WHEREAS, Section 4.2(b) of the Partnership Agreement provides that the
Partnership Securities authorized to be issued by the Partnership pursuant to
Section 4.2(a) may be issued in one more classes, or one or more series of any
such classes, with such designations, preferences and relative, participating,
optional or other special rights, powers and duties (which may be senior to
existing classes and series of Partnership Securities (except as provided in
Section 4.2(c)) as shall be fixed by the Partnership Policy Committee;

      WHEREAS, Section 15.1(f) of the Partnership Agreement provides that the
Partnership Policy Committee, without the approval of any Limited Partner or
Assignee (subject to the terms of Section 4.2 of the Partnership Agreement), may
amend any provision of the Partnership Agreement necessary or appropriate in
connection with the authorization for issuance of any class or series of
Partnership Securities pursuant to Section 4.2 of the Partnership Agreement;

      WHEREAS, the Partnership has entered into a definitive agreement, dated as
of February 14, 2006, between the Partnership and ONEOK, Inc., an Oklahoma
corporation ("ONEOK") (the "Contribution Agreement");

      WHEREAS, as part consideration for the contribution of the Shares to the
Partnership, the Contribution Agreement obligates the Partnership to issue
limited partner interests to be designated as Class B Units having the terms set
forth in this Agreement;

      WHEREAS, the Partnership Policy Committee, in consultation with the Audit
Committee, has determined that the issuance of the Class B Units provided for in
this Amendment is permitted by Section 4.2 of the Partnership Agreement; and

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      WHEREAS, Section 15.1(d)(i) of the Partnership Agreement provides that the
Partnership Policy Committee, without the approval of any Limited Partner or
Assignee, may amend any provision of the Partnership Agreement to reflect a
change that the Partnership Policy Committee determines, in its sole discretion,
does not adversely affect the Limited Partners in any material respect;

      NOW, THEREFORE, it is hereby agreed as follows:

      A.    Amendment. The Partnership Agreement is hereby amended as follows:

            1)    Section 1.1 is hereby amended to add the following
                  definitions:

                              "Class B Subordination Period" means the period
                        commencing upon issuance of the Class B Units and ending
                        on the earlier of (a) the Conversion Approval Date or
                        (b) the Conversion Approval Termination Date.

                              "Class B Unit" means a Unit representing a
                        fractional part of the Partnership Interests of all
                        Limited Partners and Assignees and having the rights and
                        obligations specified with respect to Class B Units in
                        this Agreement. Except as otherwise provided in this
                        Agreement, the term "Class B Unit" does not refer to a
                        Common Unit prior to the conversion of the Class B Unit
                        into a Common Unit pursuant to the terms hereof.

                              "Class B Unit Arrearage" means, with respect to
                        any Class B Unit, and as to any calendar quarter within
                        the Class B Subordination Period, the excess, if any, of
                        (a) the Minimum Quarterly Distribution with respect to
                        such Class B Unit (including any applicable increased
                        amounts distributable with respect to the Minimum
                        Quarterly Distribution following the Class B
                        Distribution Increase Date, the Section 4.11(b)
                        Distribution Increase Date or the GP Removal Date) over
                        (b) the sum of all Available Cash distributed with
                        respect to such Class B Unit in respect of such quarter
                        pursuant to Section 4.10(b)(ii)(A) (and Section
                        4.10(b)(ii)(A)(1) following the Class B Distribution
                        Increase Date and/or GP Removal Date, as applicable).

                              "Cumulative Class B Unit Arrearage" means, with
                        respect to any Class B Unit, and as of the end of any
                        calendar quarter (or on the expiration of the Class B
                        Subordination Period), the excess, if any, of (a) the
                        sum resulting from adding together the Class B Unit
                        Arrearage as to such Class B Unit for each of the
                        quarters within the Class B Subordination Period over
                        (b) the sum resulting from adding together (i) any
                        distributions theretofore made pursuant to Section
                        4.10(b)(ii)(B) (and Section 4.10(b)(ii)(A)(2) following
                        the Class B Distribution Increase Date and/or GP

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                        Removal Date, as applicable) with respect to such Class
                        B Unit (including any distributions to be made in
                        respect of the last of such quarters) and (ii) any
                        Cumulative Common Unit Arrearage then existing upon
                        conversion of a Class B Unit into a Common Unit pursuant
                        to the terms hereof or the occurrence of a Termination
                        Capital Transaction.

            2)    Section 1.1 is hereby amended to:

                  a)    add the following sentence to the end of the definition
                        of "Common Unit":

                              "Except as otherwise provided in this Agreement,
                        the term "Common Unit" does not refer to a Class B Unit
                        prior to the conversion of the Class B Unit into a
                        Common Unit pursuant to the terms hereof."

                  b)    add the phrase "or within the Class B Subordination
                        Period" after the phrase "and as to any calendar quarter
                        within the Subordination Period" in the definition of
                        "Common Unit Arrearage."

                  c)    add the phrase "or within the Class B Subordination
                        Period" after the phrase "for each of the quarters
                        within the Subordination Period ending on or before the
                        last day of such quarter" in clause (a) of the
                        definition of "Cumulative Common Unit Arrearage."

                  d)    add the following proviso to the end of the definition
                        of "Outstanding":

                              "; provided, further, that, except as provided in
                        Sections 4.11(a), 4.11(b), 4.12(a) and 4.12(b), none of
                        the Class B Units shall be deemed to be Outstanding for
                        purposes of determining if any Class B Units are
                        entitled to distributions of Available Cash unless such
                        Class B Units shall have been reflected on the
                        Partnership's books and records as outstanding during
                        such calendar quarter and on the Record Date for the
                        determination of any distribution of Available Cash;"

                  e)    [Intentionally Omitted]

            3)    Article IV is hereby amended to add new Sections 4.10 - 4.13
                  creating a new class of Units as follows:

                  SECTION 4.10 ESTABLISHMENT OF CLASS B UNITS.

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                  a)    General. The Partnership Policy Committee hereby
                        designates and creates a class of Units to be designed
                        as "Class B Units" and consisting of a total of
                        36,494,126 Class B Units, and fixes the designations,
                        preferences and relative, participating, optional or
                        other special rights, power and duties of holders of the
                        Class B Units as set forth in this Section 4.10.

                  b)    Rights Associated with Class B Units. During the period
                        commencing upon issuance of the Class B Units and ending
                        upon the conversion of the Class B Units as set forth in
                        Section 4.10(f) hereof, unless amended pursuant to
                        Section 4.11 or Section 4.12 hereof:

                        i)    subject to the provisions of Section
                              5.1(d)(iii)(A), and unless clauses (ii), (iii), or
                              (iv) below require a different allocation pursuant
                              to Section 5.1(c)(i) or otherwise, all items of
                              Partnership income, gain, loss, deduction and
                              credit shall be allocated to the Class B Units to
                              the same extent as such items would be so
                              allocated if such Class B Units were Common Units
                              that were then Outstanding;

                        ii)   Notwithstanding anything to the contrary in
                              Section 5.4, with respect to distributions made in
                              accordance with Section 5.4 for calendar quarters
                              ending on or prior to the expiration of the Class
                              B Subordination Period, the Class B Units shall be
                              deemed Units, but not Common Units, for such
                              purposes and, in addition, the holders of Class B
                              Units shall have the right to share in Partnership
                              quarterly cash distributions in accordance with
                              Section 5.4 hereof (such distribution to be
                              prorated for the quarter in which the Class B
                              Units are issued), provided that following any
                              distribution pursuant to Section 5.4(c) and prior
                              to any distribution pursuant to Section 5.4(d),
                              Available Cash shall be distributed as follows:

                              (A)   99% to the holders of Class B Units and 1%
                                    to the General Partners, in accordance with
                                    their relative General Partner Percentage
                                    Interests, until there has been distributed
                                    in respect of each Class B Unit Outstanding
                                    as of the last day of such quarter an amount
                                    equal to the Minimum Quarterly Distribution;
                                    and

                              (B)   then, 99% to the holders of Class B Units
                                    and 1% to the General Partners, in
                                    accordance with their relative General
                                    Partner Percentage Interests, until there
                                    has been distributed in respect of each
                                    Class B

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                                    Unit Outstanding as of the last day of such
                                    quarter an amount equal to the Cumulative
                                    Class B Unit Arrearage, if any, existing
                                    with respect to such quarter.

                        iii)  The holders of Class B Units shall have the right
                              to share in Partnership quarterly cash
                              distributions for quarters ending after the
                              expiration of the Class B Subordination Period in
                              accordance with Section 5.4 hereof as if such
                              holders of Class B Units held Common Units and, in
                              addition, notwithstanding anything to the contrary
                              set forth in Section 5.4, if a Cumulative Class B
                              Unit Arrearage exists on the date of the
                              expiration of the Class B Subordination Period,
                              prior to any distribution pursuant to Section
                              5.4(d), irrespective of whether any such Class B
                              Units are then Outstanding, Available Cash shall
                              be distributed in accordance with Section
                              4.10(b)(ii)(B) hereof to each holder of record of
                              the applicable Class B Units as of the expiration
                              of the Class B Subordination Period. This
                              distribution shall not be deemed a distribution on
                              a Common Unit, but the satisfaction of prior
                              entitlements of the holders of Class B Units as of
                              the expiration of the Class B Subordination
                              Period. For the taxable year in which such
                              distribution is made, if not previously allocated,
                              each Person receiving such cash distribution shall
                              be allocated items of gross income in an amount
                              equal to such distribution as provided in Section
                              5.1(d)(iii)(A).

                        iv)   Notwithstanding anything to the contrary in
                              Section 5.1(c)(i), during the Class B
                              Subordination Period the Class B Units shall be
                              treated as Common Units then Outstanding for
                              purposes of Section 5.1(c)(i), and, in addition,
                              following any allocation made pursuant to Section
                              5.1(c)(i)(B) and before an allocation is made
                              pursuant to Section 5.1(c)(i)(C), any remaining
                              Net Termination Gain shall be allocated 99% to the
                              holders of the Class B Units and 1% to the General
                              Partners, in accordance with their relative
                              General Partner Percentage Interests, until each
                              such holder of a Class B Unit has been allocated
                              Net Termination Gain equal to any then existing
                              Cumulative Class B Unit Arrearage with respect to
                              such Class B Unit.

                  c)    Voting Rights. Unless amended pursuant to Section 4.11
                        or Section 4.12 hereof, (i) during the Class B
                        Subordination Period, the Class B Units are non-voting
                        (and solely for all purposes of calculating votes and
                        determining the presence of a quorum under this
                        Agreement, none of the Class B Units shall be deemed
                        Outstanding), except that the Class B Units shall be
                        entitled to vote

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                        as a separate class on any matter that adversely affects
                        the rights or preferences of the Class B Units in
                        relation to other classes of Partnership Interests or as
                        required by law. The approval of a majority of the Class
                        B Units shall be required to approve any matter for
                        which the holders of the Class B Units are entitled to
                        vote as a separate class, and (ii) upon expiration of
                        the Class B Subordination Period, the Class B Units will
                        have such voting rights pursuant to the Partnership
                        Agreement as such Class B Units would have if they were
                        Common Units that were then Outstanding except that,
                        with respect to the Conversion Approval or Amendment
                        Approval, none of the Class B Units shall be deemed
                        Outstanding as of the record date for such vote or be
                        entitled to vote. Each Class B Unit will be entitled to
                        the number of votes equal to the number of Common Units
                        into which a Class B Unit is convertible at the time of
                        the record date for the vote or written consent on the
                        matter.

                  d)    Certificates. The Class B Units will be evidenced by
                        certificates in such form as the Partnership Policy
                        Committee may approve and, subject to the satisfaction
                        of any applicable legal and regulatory requirements, may
                        be assigned or transferred in a manner identical to the
                        assignment and transfer of other Units. The Certificates
                        will include the restrictive legend set forth in Section
                        2.17 of the Contribution Agreement.

                  e)    Registrar and Transfer Agent. Northern Plains will act
                        as registrar and transfer agent of the Class B Units.

                  f)    Conversion. Except as provided in this Section 4.10(f),
                        the Class B Units are not convertible into Common Units.

                        i)    Optional Conversion. The Partnership shall, as
                              promptly as practicable following the issuance of
                              any Class B Units, take such actions as may be
                              necessary or appropriate to submit to a vote or
                              consent of its securityholders the approval of a
                              change in the terms of the Class B Units to
                              provide that each Class B Unit shall be
                              convertible from time to time, at the option of
                              the holders thereof, into one Common Unit (subject
                              to appropriate adjustment in the event of any
                              split-up, combination or similar event affecting
                              the Common Units that occurs prior to the
                              conversion of the Class B Units), effective upon
                              approval of the issuance of additional Common
                              Units in accordance with the following sentence
                              (the "Conversion Approval"). The vote or consent
                              required for such approval will be the requisite
                              vote required under the rules or staff
                              interpretations of the National Securities
                              Exchange on which the Common Units are listed or
                              admitted for trading for the listing or addition
                              to

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                              trading of the Common Units that would be issued
                              upon such conversion, excluding those Units held
                              by ONEOK and its affiliates. Upon receipt of the
                              required vote or consent (the date of such
                              approval, the "Conversion Approval Date"), the
                              terms of the Class B Units will be changed,
                              automatically and without further action, so that
                              each Class B Unit may be converted, at the option
                              of the holder thereof, into one Common Unit
                              (subject to appropriate adjustment in the event of
                              any split-up, combination or similar event
                              affecting the Common Units that occurs prior to
                              the conversion of the Class B Units).

                        ii)   Automatic Conversion. The Partnership shall, as
                              promptly as practicable following the issuance of
                              any Class B Units, take such actions as may be
                              necessary or appropriate to submit to a vote or
                              consent of holders of at least 66 2/3% of the
                              Outstanding Units (excluding those Units held by
                              ONEOK and its Affiliates) and otherwise as
                              required by Section 15.2 of the Partnership
                              Agreement, the amendments to the Partnership
                              Agreement described on Annex A (the approval of
                              such amendment, the "Amendment Approval," and the
                              date of obtaining the Amendment Approval, the
                              "Amendment Approval Date"). Subject to Section
                              4.12, each Class B Unit shall automatically
                              convert into one Common Unit (subject to
                              appropriate adjustment in the event of any
                              split-up, combination or similar event affecting
                              the Common Units that occurs prior to the
                              conversion of the Class B Units) upon receipt of:

                                (A)   Conversion Approval as set forth above in
                                      paragraph (i); and

                                (B)   Amendment Approval as set forth above in
                                      this paragraph (ii);

                        and immediately thereafter, none of the Class B Units
                        shall be outstanding.

                        iii)  Quarterly Cash Distributions. Each Common Unit
                              into which a Class B Unit has been converted as
                              provided in this Section 4.10(f) shall have the
                              right to share in any Partnership quarterly cash
                              distributions made in respect of a Common Unit in
                              accordance with Section 5.4 hereof (including,
                              without limitation and not withstanding anything
                              to the contrary contained in the Partnership
                              Agreement, the right to any distributions of
                              amounts in

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                              respect of Cumulative Common Unit Arrearages in
                              respect of a Common Unit).

                        SECTION 4.11 AMENDMENT OF TERMS OF CLASS B UNITS IF
                        SECURITYHOLDER APPROVAL IS NOT OBTAINED.

                        a)    If:

                              i)    the Conversion Approval has not been
                                    obtained by the date that is 12 months
                                    following the Closing (as defined under the
                                    Contribution Agreement); and

                              ii)   the Amendment Approval has not been obtained
                                    by the date that is 12 months following the
                                    Closing;

                              then, unless the provisions of Section 4.12 shall
                              already be in effect, effective as of the next
                              succeeding day (the "Class B Distribution Increase
                              Date") until amended by the provisions of Section
                              4.12, Sections 4.10(b) and 4.10(c) hereof will be
                              deemed to be amended in their entirety,
                              automatically and without further action, as
                              follows:

                        "b) Rights Associated with Class B Units. Prior to the
                        conversion of all of the Class B Units pursuant to
                        Section 4.10(f) above:

                              i)    subject to the provisions of Section
                                    5.1(d)(iii)(A) and paragraphs (ii) and (iii)
                                    below, all items of Partnership income,
                                    gain, loss, deduction and credit shall be
                                    allocated to the Class B Units to the same
                                    extent such items would be allocated if such
                                    Class B Units were Common Units then
                                    Outstanding, and the allocations to Class B
                                    Units shall have the same order of priority
                                    relative to allocations on the Common Units;

                              ii)(A) notwithstanding anything to the contrary in
                                    Section 5.4, the Class B Units shall be
                                    deemed Units, but not Common Units, for
                                    purposes of Section 5.4 and the Class B
                                    Units shall have the right to share in
                                    Partnership quarterly cash distributions in
                                    accordance with Section 5.4 hereof based on
                                    115% of the amount of any Partnership
                                    distribution that would be made to each
                                    Common Unit so that the amount of any
                                    Partnership distribution to each Class B
                                    Unit will equal 115% of the amount of such
                                    distribution to each Common Unit (such
                                    additional 15% pro rated for the quarter in
                                    which the Class B Distribution Increase Date
                                    occurs), provided, however, that following
                                    any distribution pursuant to Section 5.4(c)
                                    and prior to any distribution pursuant to
                                    Section 5.4(d), Available Cash shall be
                                    distributed as follows:

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                                       (1) 99% to the holders of Class B Units
                                       and 1% to the General Partners, in
                                       accordance with their relative General
                                       Partner Percentage Interests, until there
                                       has been distributed in respect of each
                                       Class B Unit Outstanding as of the last
                                       day of such quarter an amount equal to
                                       115% of the Minimum Quarterly
                                       Distribution; and

                                       (2) then, 99% to the holders of Class B
                                       Units and 1% to the General Partners, in
                                       accordance with their relative General
                                       Partner Percentage Interests, until there
                                       has been distributed in respect of each
                                       Class B Unit Outstanding as of the last
                                       day of such quarter an amount equal to
                                       the Cumulative Class B Unit Arrearage, if
                                       any, existing with respect to such
                                       quarter.

                                    (B) notwithstanding anything to the contrary
                                    contained in Section 5.4, if a Cumulative
                                    Class B Unit Arrearage exists on the date of
                                    the expiration of the Class B Subordination
                                    Period, prior to any distribution pursuant
                                    to Section 5.4(d), irrespective of whether
                                    any such Class B Units are then Outstanding,
                                    Available Cash shall be distributed 99% to
                                    the holders of record of the applicable
                                    Class B Units as of the expiration of the
                                    Class B Subordination Period and 1% to the
                                    General Partners, in accordance with their
                                    relative General Partner Percentage
                                    Interests, until there has been distributed
                                    in respect of each Class B Unit an amount
                                    equal to the Cumulative Class B Unit
                                    Arrearage, if any, existing with respect to
                                    such quarter. This distribution shall not be
                                    deemed a distribution on a Common Unit, but
                                    the satisfaction of prior entitlements of
                                    the holders of Class B Units as of the
                                    expiration of the Class B Subordination
                                    Period. For the taxable year in which such
                                    distribution is made, if not previously
                                    allocated, each Person receiving such cash
                                    distribution shall be allocated items of
                                    gross income in an amount equal to such
                                    distribution as provided in Section
                                    5.1(d)(iii)(A); and

                              iii)  the Class B Units shall have rights upon
                                    dissolution and liquidation of the
                                    Partnership, including the right to share in
                                    any liquidating distributions, that are
                                    based on 115% of the liquidating
                                    distributions that would be made to the
                                    Common Units so that the amount of any
                                    liquidating distribution to each Class B
                                    Unit will equal 115% of the amount of such
                                    distribution to each Common Unit, and, in
                                    addition, following any allocation made
                                    pursuant to Section 5.1(c)(i)(B) and before
                                    an allocation is made pursuant to Section
                                    5.1(c)(i)(C), any remaining Net Termination
                                    Gain shall be allocated 99% to

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                                    the holders of the Class B Units and 1% to
                                    the General Partners, in accordance with
                                    their relative General Partner Percentage
                                    Interests, until each such holder of a Class
                                    B Unit has been allocated Net Termination
                                    Gain equal to any then existing Cumulative
                                    Class B Unit Arrearage with respect to such
                                    Class B Unit, and accordingly,
                                    notwithstanding anything to the contrary in
                                    this Agreement, prior to any distribution
                                    under Section 14.3, the Capital Account of
                                    each Partner shall be adjusted to give
                                    effect to the foregoing liquidation rights.

                              c) Voting Rights. The Class B Units will have such
                              voting rights pursuant to the Partnership
                              Agreement as such Class B Units would have if they
                              were Common Units that were then Outstanding
                              except that, with respect to the Conversion
                              Approval or Amendment Approval, none of the Class
                              B Units shall be deemed Outstanding as of the
                              record date for such vote or be entitled to vote.
                              Each Class B Unit will be entitled to the number
                              of votes equal to the number of Common Units into
                              which a Class B Unit is convertible at the time of
                              the record date for the vote or written consent on
                              the matter."

                        (b    If:

                                  i)  the Conversion Approval has been obtained
                                      by the date that is 12 months following
                                      the Closing (as defined under the
                                      Contribution Agreement); and

                                  ii) the Amendment Approval has not been
                                      obtained by the date that is 12 months
                                      following the Closing;

                                  then, unless the provisions of Section 4.12
                                  shall already be in effect, effective as of
                                  the next succeeding day (the "Section 4.11(b)
                                  Distribution Increase Date") until amended by
                                  the provisions of Section 4.12, Sections
                                  4.10(b) and 4.10(c) hereof will be deemed to
                                  be amended in their entirety, automatically
                                  and without further action, as follows:

                              "b) Rights Associated with Class B Units. Prior to
                              the conversion of all of the Class B Units
                              pursuant to Section 4.10(f) above:

                                  i)  subject to the provisions of Section
                                      5.1(d)(iii)(A) and paragraphs (ii) and
                                      (iii) below, all items of Partnership
                                      income, gain, loss, deduction and credit
                                      shall be allocated to the Class B Units to
                                      the same extent such items would be
                                      allocated if such Class B Units were
                                      Common Units then Outstanding, and the
                                      allocations to Class B Units shall have
                                      the same order of priority relative to
                                      allocations on the Common Units;

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<PAGE>

                                  ii) (A) the Class B Units shall have the right
                                      to share in Partnership quarterly cash
                                      distributions based on 115% of the amount
                                      of any Partnership distribution that would
                                      be made to each Common Unit so that the
                                      amount of any Partnership distribution to
                                      each Class B Unit will equal 115% of the
                                      amount of such distribution to each Common
                                      Unit (such additional 15% pro rated for
                                      the quarter in which the Class B
                                      Distribution Increase Date occurs), and
                                      the right of holders of Class B Units to
                                      receive distributions shall have the same
                                      order of priority relative to
                                      distributions on the Common Units; and

                                      (B) notwithstanding anything to the
                                      contrary contained in Section 5.4, if a
                                      Cumulative Class B Unit Arrearage existed
                                      on the date of the expiration of the Class
                                      B Subordination Period, prior to any
                                      distribution pursuant to Section 5.4(d),
                                      irrespective of whether any such Class B
                                      Units are then Outstanding, Available Cash
                                      shall be distributed 99% to the holders of
                                      record of the applicable Class B Units as
                                      of the expiration of the Class B
                                      Subordination Period and 1% to the General
                                      Partners, in accordance with their
                                      relative General Partner Percentage
                                      Interests, until there has been
                                      distributed in respect of each Class B
                                      Unit an amount equal to the Cumulative
                                      Class B Unit Arrearage, if any, existing
                                      with respect to such quarter. This
                                      distribution shall not be deemed a
                                      distribution on a Common Unit, but the
                                      satisfaction of prior entitlements of the
                                      holders of Class B Units as of the
                                      expiration of the Class B Subordination
                                      Period. For the taxable year in which such
                                      distribution is made, if not previously
                                      allocated, each Person receiving such cash
                                      distribution shall be allocated items of
                                      gross income in an amount equal to such
                                      distribution as provided in Section
                                      5.1(d)(iii)(A); and

                                  iii) the Class B Units shall have rights upon
                                      dissolution and liquidation of the
                                      Partnership, including the right to share
                                      in any liquidating distributions, that are
                                      based on 115% of the liquidating
                                      distributions that would be made to the
                                      Common Units so that the amount of any
                                      liquidating distribution to each Class B
                                      Unit will equal 115% of the amount of such
                                      distribution to each Common Unit, and, in
                                      addition, following any allocation made
                                      pursuant to Section 5.1(c)(i)(B) and
                                      before an allocation is made pursuant to
                                      Section 5.1(c)(i)(C), any remaining Net
                                      Termination Gain shall be allocated 99% to
                                      the holders of the Class B Units and 1% to
                                      the General Partners, in accordance with
                                      their relative General Partner Percentage
                                      Interests, until each such holder of a
                                      Class B Unit

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<PAGE>

                                      has been allocated Net Termination Gain
                                      equal to any then existing Cumulative
                                      Class B Unit Arrearage with respect to
                                      such Class B Unit, and accordingly,
                                      notwithstanding anything to the contrary
                                      in this Agreement, prior to any
                                      distribution under Section 14.3, the
                                      Capital Account of each Partner shall be
                                      adjusted to give effect to the foregoing
                                      liquidation rights.

                              c) Voting Rights. The Class B Units will have such
                              voting rights pursuant to the Partnership
                              Agreement as such Class B Units would have if they
                              were Common Units that were then Outstanding
                              except that, with respect to the Conversion
                              Approval or Amendment Approval, none of the Class
                              B Units shall be deemed Outstanding as of the
                              record date for such vote or be entitled to vote.
                              Each Class B Unit will be entitled to the number
                              of votes equal to the number of Common Units into
                              which a Class B Unit is convertible."

                        c) If a Class B Distribution Increase Date or Section
                        4.11(b) Distribution Increase Date has occurred and the
                        Partnership's securityholders thereafter either (1)
                        obtain the Conversion Approval and the Amendment
                        Approval, or (2) any of the Class B Units are converted
                        into Common Units pursuant to Section 4.10(f)(i), then,
                        unless the provisions of Section 4.12 shall already be
                        in effect, (i) with respect to the matters described in
                        sub-clause (1) above, as of the later of the Conversion
                        Approval Date and the Amendment Approval Date, all Class
                        B Units shall automatically, and without further action
                        of the holder(s) thereof, be converted into Common Units
                        in accordance with Section 4.10(f)(ii), and (ii) with
                        respect to matters described in sub-clauses (1) and (2)
                        above for the quarter in which such conversion occurs,
                        concurrently with the distribution made in accordance
                        with Article V of the Partnership Agreement of Available
                        Cash, with respect to the quarter in which the
                        conversion of the Class B Units is effected, a
                        distribution shall be paid to each holder of record of
                        the applicable Class B Units as of the effective date of
                        such conversion, with the amount of such distribution
                        for each such Class B Unit to be equal to the product of
                        (a) 15% of the amount to be distributed in respect of
                        such quarter to each Common Unit times (it being agreed
                        that each such Common Unit issued upon conversion shall
                        be entitled to the full distribution payable to the
                        holder of a Common Unit) and (b) a fraction, of which
                        (A) the numerator is the number of days in such quarter
                        up to but excluding the date of such conversion, and (B)
                        the denominator is the total number of days in such
                        quarter (the foregoing amount being referred to as an
                        "Excess Payment"). For the taxable year in which an
                        Excess Payment is made, each holder of a Class B Unit
                        shall be allocated items of gross income with respect to
                        such taxable year in an amount equal to the Excess
                        Payment distributed to it as provided in Section
                        5.1(d)(iii)(A).

      SECTION 4.12 AMENDMENT OF TERMS OF CLASS B UNITS UPON REMOVAL OF THE
      GENERAL PARTNER.

                                       12

<PAGE>

      a) If prior to the conversion of all Class B Units, a resolution of the
      Limited Partners holding the requisite majority of Outstanding Units is
      passed approving the removal of any Affiliate of ONEOK as the general
      partner of the Partnership (a "GP Removal Event") and the Conversion
      Approval has not been obtained, then notwithstanding Section 4.11,
      automatically and without further action and, effective as of the next
      succeeding day (the "GP Removal Date"), Section 4.10(f)(ii) shall be
      deemed to be deleted in its entirety, automatically and without further
      action, and Sections 4.10(b) and 4.10(c) hereof will be deemed to be
      amended in their entirety, automatically and without further action, as
      follows:

                  "b) Rights Associated with Class B Units. Prior to the
                  conversion of the Class B Units as set forth in Section
                  4.10(f) hereof:

                        i)  subject to the provisions of Section 5.1(d)(iii)(A)
                            and paragraphs (ii) and (iii) below, all of items
                            Partnership income, gain, loss, deduction and credit
                            shall be allocated to the Class B Units to the same
                            extent as such items would be allocated if such
                            Class B Units were Common Units then Outstanding,
                            and the allocations to Class B Units shall have the
                            same order of priority relative to allocations on
                            the Common Units; and

                        ii) (A) notwithstanding anything to the contrary in
                            Section 5.4, the Class B Units shall be deemed
                            Units, but not Common Units, for purposes of Section
                            5.4 and the Class B Units shall have the right to
                            share in Partnership quarterly cash distributions in
                            accordance with Section 5.4 hereof based on 125% of
                            the amount of any Partnership distribution that
                            would be made to each Common Unit so that the amount
                            of any Partnership distribution to each Class B Unit
                            will equal 125% of the amount of such distribution
                            to each Common Unit (such additional 25% pro rated
                            for the quarter in which the GP Removal Date
                            occurs), provided, however, that following any
                            distribution pursuant to Section 5.4(c) and prior to
                            any distribution pursuant to Section 5.4(d),
                            Available Cash shall be distributed as follows:

                              (1) 99% to the holders of Class B Units and 1% to
                              the General Partners, in accordance with their
                              relative General Partner Percentage Interests,
                              until there has been distributed in respect of
                              each Class B Unit Outstanding as of the last day
                              of such quarter an amount equal to 125% of the
                              Minimum Quarterly Distribution; and

                              (2) then, 99% to the holders of Class B Units and
                              1% to the General Partners, in accordance with
                              their relative General Partner Percentage
                              Interests, until there has been

                                       13

<PAGE>

                              distributed in respect of each Class B Unit
                              Outstanding as of the last day of such quarter an
                              amount equal to the Cumulative Class B Unit
                              Arrearage, if any, existing with respect to such
                              quarter.

                        (B)notwithstanding anything to the contrary in Section
                        5.4, if a Cumulative Class B Unit Arrearage exists on
                        the date of the expiration of the Class B Subordination
                        Period, prior to any distribution pursuant to Section
                        5.4(d), irrespective of whether any such Class B Units
                        are then Outstanding, Available Cash shall be
                        distributed 99% to the holders of record of the
                        applicable Class B Units as of the expiration of the
                        Class B Subordination Period and 1% to the General
                        Partners, in accordance with their relative General
                        Partner Percentage Interests, until there has been
                        distributed in respect of each Class B Unit an amount
                        equal to the Cumulative Class B Unit Arrearage, if any,
                        existing with respect to such quarter. This distribution
                        shall not be deemed a distribution on a Common Unit, but
                        the satisfaction of prior entitlements of the holders of
                        Class B Units as of the expiration of the Class B
                        Subordination Period. For the taxable year in which such
                        distribution is made, if not previously allocated, each
                        Person receiving such cash distribution shall be
                        allocated items of gross income in an amount equal to
                        such distribution as provided in Section 5.1(d)(iii)(A);
                        and

                  iii)  the Class B Units shall have rights upon dissolution and
                        liquidation of the Partnership, including the right to
                        share in any liquidating distributions, that are based
                        on 125% of the liquidating distributions that would be
                        made to the Common Units so that the amount of any
                        liquidating distribution to each Class B Unit will equal
                        125% of the amount of such distribution to each Common
                        Unit, and, in addition, following any allocation made
                        pursuant to Section 5.1(c)(i)(B) and before an
                        allocation is made pursuant to Section 5.1(c)(i)(C), any
                        remaining Net Termination Gain shall be allocated 99% to
                        the holders of the Class B Units and 1% to the General
                        Partners, in accordance with their relative General
                        Partner Percentage Interests, until each such holder of
                        a Class B Unit has been allocated Net Termination Gain
                        equal to any then existing Cumulative Class B Unit
                        Arrearage with respect to such Class B Unit, and
                        accordingly, notwithstanding anything to the contrary in
                        this Agreement, prior to any distribution under Section
                        14.3, the Capital Account of each Partner shall be
                        adjusted to give effect to the foregoing liquidation
                        rights.

                                       14

<PAGE>

                  c) Voting Rights. The Class B Units will have such voting
                  rights pursuant to the Partnership Agreement as such Class B
                  Units would have if they were Common Units that were then
                  Outstanding except that, (i) for the purposes of the
                  definition of "Outstanding" such Class B Units shall be deemed
                  to be "Units," but not "Common Units," for all purposes
                  thereof and (ii) with respect to the Conversion Approval (if
                  not already obtained), none of the Class B Units shall be
                  deemed Outstanding as of the record date for such vote or be
                  entitled to vote . Each Class B Unit will be entitled to one
                  vote on each matter with respect to which such Class B Unit is
                  entitled to be voted."

      b) If, the Conversion Approval has been obtained and a GP Removal Event
      occurs, then notwithstanding Section 4.11, automatically and without
      further action and, effective as of the GP Removal Date, Section
      4.10(f)(ii) shall be deemed to be deleted in its entirety, automatically
      and without further action, and Sections 4.10(b) and 4.10(c) hereof will
      be deemed to be amended in their entirety, automatically and without
      further action, as follows:

                  "b) Rights Associated with Class B Units. Prior to the
                  conversion of the Class B Units as set forth in Section
                  4.10(f) hereof:

                        i)  subject to the provisions of Section 5.1(d)(iii)(A)
                            and paragraphs (ii) and (iii) below, all of items
                            Partnership income, gain, loss, deduction and credit
                            shall be allocated to the Class B Units to the same
                            extent as such items would be allocated if such
                            Class B Units were Common Units then Outstanding,
                            and the allocations to Class B Units shall have the
                            same order of priority relative to allocations on
                            the Common Units; and

                        ii)(A) the Class B Units shall have the right to share
                            in Partnership quarterly cash distributions based on
                            125% of the amount of any Partnership distribution
                            that would be made to each Common Unit so that the
                            amount of any Partnership distribution to each Class
                            B Unit will equal 125% of the amount of such
                            distribution to each Common Unit (such additional
                            25% pro rated for the quarter in which the GP
                            Removal Date occurs), and the right of holders of
                            Class B Units to receive distributions shall have
                            the same order of priority relative to distributions
                            on the Common Units; and,

                            (B)notwithstanding anything to the contrary in
                            Section 5.4, if a Cumulative Class B Unit Arrearage
                            existed on the date of the expiration of the Class B
                            Subordination Period, prior to any distribution
                            pursuant to Section 5.4(d), irrespective of whether
                            any such Class B Units are then Outstanding,
                            Available Cash shall be distributed 99% to the

                                       15

<PAGE>

                            holders of record of the applicable Class B Units as
                            of the expiration of the Class B Subordination
                            Period and 1% to the General Partners, in accordance
                            with their relative General Partner Percentage
                            Interests, until there has been distributed in
                            respect of each Class B Unit an amount equal to the
                            Cumulative Class B Unit Arrearage, if any, existing
                            with respect to such quarter. This distribution
                            shall not be deemed a distribution on a Common Unit,
                            but the satisfaction of prior entitlements of the
                            holders of Class B Units as of the expiration of the
                            Class B Subordination Period. For the taxable year
                            in which such distribution is made, if not
                            previously allocated, each Person receiving such
                            cash distribution shall be allocated items of gross
                            income in an amount equal to such distribution as
                            provided in Section 5.1(d)(iii)(A); and

                        iii) the Class B Units shall have rights upon
                            dissolution and liquidation of the Partnership,
                            including the right to share in any liquidating
                            distributions, that are based on 125% of the
                            liquidating distributions that would be made to the
                            Common Units so that the amount of any liquidating
                            distribution to each Class B Unit will equal 125% of
                            the amount of such distribution to each Common Unit,
                            and, in addition, following any allocation made
                            pursuant to Section 5.1(c)(i)(B) and before an
                            allocation is made pursuant to Section 5.1(c)(i)(C),
                            any remaining Net Termination Gain shall be
                            allocated 99% to the holders of the Class B Units
                            and 1% to the General Partners, in accordance with
                            their relative General Partner Percentage Interests,
                            until each such holder of a Class B Unit has been
                            allocated Net Termination Gain equal to any then
                            existing Cumulative Class B Unit Arrearage with
                            respect to such Class B Unit, and accordingly,
                            notwithstanding anything to the contrary in this
                            Agreement, prior to any distribution under Section
                            14.3, the Capital Account of each Partner shall be
                            adjusted to give effect to the foregoing liquidation
                            rights.

                  c) Voting Rights. The Class B Units will have such voting
                  rights pursuant to the Partnership Agreement as such Class B
                  Units would have if they were Common Units that were then
                  Outstanding except that, for the purposes of the definition of
                  "Outstanding" such Class B Units shall be deemed to be
                  "Units", but not "Common Units" for all purposes thereof. Each
                  Class B Unit will be entitled to one vote on each matter with
                  respect to which such Class B Unit is entitled to be voted."

            c) If a GP Removal Event has occurred and any of the Class B Units
            are converted into Common Units pursuant to Section 4.10(f)(i),
            then, for the quarter in which such conversion occurs, concurrently
            with the distribution made in

                                       16

<PAGE>

            accordance with Article V of the Partnership Agreement of Available
            Cash, with respect to the quarter in which the conversion of the
            Class B Units is effected, a distribution shall be paid to each
            holder of record of the applicable Class B Units as of the effective
            date of such conversion, with the amount of such distribution for
            each such Class B Unit to be equal to the product of (a) 25% of the
            amount to be distributed in respect of such quarter to each Common
            Unit times (it being agreed that each such Common Unit issued upon
            conversion shall be entitled to the full dividend payable to the
            holder of a Common Unit) (b) a fraction, of which (i) the numerator
            is the number of days in such quarter up to but excluding the date
            of such conversion, and (ii) the denominator is the total number of
            days in such quarter (the foregoing amount being referred to as an
            "Excess Payment"). For the taxable year in which an Excess Payment
            is made, each holder of a Class B Unit shall be allocated items of
            gross income with respect to such taxable year in an amount equal to
            the Excess Payment distributed to it as provided in Section
            5.1(d)(iii)(A).

            SECTION 4.13 CHANGE OF NEW YORK STOCK EXCHANGE RULES OR
                         INTERPRETATIONS.

            If at any time (i) the rules of the National Securities Exchange on
            which the Common Units are listed or admitted to trading or the
            staff interpretations of such rules are changed, or (ii) facts and
            circumstances arise so that the Conversion Approval is no longer
            required as a condition to the listing of the Common Units that
            would be issued upon any conversion of any Class B Units into Common
            Units as provided in Section 4.10(f)(i) hereof as determined by the
            Partnership Policy Committee (the date that the Partnership Policy
            Committee makes such determination, the "Conversion Approval
            Termination Date") and the Amendment Approval has been obtained,
            then, unless the provisions of Section 4.12 shall already be in
            effect, the terms of such Class B Units will be changed so that each
            such Class B Unit is converted (without further action or any vote
            of any securityholders of the Partnership) into one Common Unit
            (subject to appropriate adjustment in the event of any split-up,
            combination or similar event affecting the Common Units).

      B. Agreement in Effect. Except as hereby amended, the Partnership
Agreement shall remain in full force and effect.

      C. Applicable Law. This Amendment shall be construed in accordance with
and governed by the laws of the State of Delaware.

      D. Invalidity of Provisions. If any provision of this Amendment is or
becomes invalid, illegal or unenforceable in any respect, the validity, legality
and enforceability of the remaining provisions contained herein shall not be
effected thereby.

      E. Counterparts. This Amendment may be executed in counterparts, all of
which together shall constitute an agreement binding on all parties thereto,
notwithstanding that all such parties are not signatories to the original or the
same counterpart.

                                       17

<PAGE>

                              General Partners:

                              Northern Plains Natural Gas Company, LLC

                              /s/ Jerry L. Peters
                              --------------------------------------------------
                              Name:  Jerry L. Peters
                              Title: Vice President, Finance and Treasurer


                              Northwest Border Pipeline Company

                              /s/ David L. Kyle
                              --------------------------------------------------
                              Name:  David L. Kyle
                              Title: Chairman of the Policy Committee


                              Pan Border Gas Company, LLC

                              /s/ Jerry L. Peters
                              --------------------------------------------------
                              Name:  Jerry L. Peters
                              Title: Vice President, Finance and Treasurer


                              Limited Partners:

                              All Limited Partners now and hereafter admitted as
                              limited partner of the Partnership, pursuant to
                              Powers of Attorney now and hereafter executed in
                              favor of, and granted and delivered to, the
                              Members of the Partnership Policy Committee.

                              Chairman of the Partnership Policy Committee, as
                              attorney-in-fact for all Limited Partners pursuant
                              to the Powers of Attorney granted in Section 1.4

                                       18

<PAGE>

                                     ANNEX A

1.    THE FOLLOWING DEFINITIONS SHALL BE DELETED IN THEIR ENTIRETY FROM ARTICLE
      II:

      "GROSS GENERAL PARTNER PERCENTAGE INTEREST"; AND

      "HYPOTHETICAL EQUITY VALUE".

2.    SECTION 13.2 SHALL BE AMENDED TO READ IN ITS ENTIRETY AS FOLLOWS:

      "Section 13.2 Removal of the General Partner.

            The General Partner may be removed if such removal is approved by
      the Unitholders holding at least 66 2/3% of the Outstanding Units
      (including for purposes of such determination Units held by the General
      Partner and its Affiliates) voting as a single class. Any such action by
      such holders for removal of the General Partner must also provide for the
      election of a successor General Partner by the Unitholders holding a
      majority of the outstanding Common Units voting as a class (including for
      purposes of such determination Units held by the General Partner and its
      Affiliates). Such removal shall be effective immediately following the
      admission of a successor General Partner. The removal of the General
      Partner shall also automatically constitute the removal of the General
      Partner as general partner or managing member, to the extent applicable,
      of the Intermediate Partnership and any other Group Members of which the
      General Partner is a general partner or managing member. If a Person is
      elected as a successor General Partner in accordance with the terms of
      this Section 13.2, such Person shall, upon admission pursuant to Article
      XII, automatically become a successor general partner or managing member,
      to the extent applicable, of the Intermediate Partnership and any other
      Group Members of which the General Partner is a general partner of a
      managing member. The right of the holders of Outstanding Units to remove
      the General Partner shall not exist or be exercised unless the Partnership
      has received an opinion opining as to the matters covered by a Withdrawal
      Opinion of Counsel. Any successor General Partner elected in accordance
      with the terms of this Section 13.2 shall be subject to the provisions of
      Section 12.3."

3. THE SECOND PARAGRAPH OF SECTION 13.3(a) SHALL BE AMENDED TO READ IN ITS
ENTIRETY AS FOLLOWS:

            "For purposes of this Section 13.3(a), the fair market value of the
      Departing Partner's Combined Interest shall be determined by agreement
      between the Departing Partner and its successor or, failing agreement
      within 30 days after the effective date of such Departing Partner's
      departure, by an independent investment banking firm or other independent
      expert selected by the Departing Partner and its successor, which, in
      turn, may rely on other experts, and the determination of which shall be
      conclusive as to such matter. If such parties cannot agree upon one
      independent investment banking firm or other independent expert within 45
      days after the effective date of such departure, then the Departing
      Partner shall designate an independent investment banking firm or other
      independent expert, the Departing Partner's successor shall designate an
      independent investment banking firm or other independent expert, which
      third independent investment banking firm or other independent expert


<PAGE>

      shall determine the fair market value of the Combined Interest of the
      Departing Partner. In making its determination, such third independent
      investment banking firm or other independent expert may consider the then
      current trading price of Units on any National Securities Exchange on
      which Units are then listed or admitted to trading, the value of the
      Partnership's assets, the rights and obligations of the Departing Partner
      and other factors it may deem relevant."

4.    SECTION 13.3(b) SHALL BE AMENDED TO READ IN ITS ENTIRETY AS FOLLOWS:

      (b) If the Combined Interest of a Departing Partner is not acquired by one
      or more of the remaining General Partners pursuant to Section 11.7(b) or
      by a successor in the manner set forth in Section 13.3(a), the Departing
      Partner shall become a Limited Partner and the Combined Interest shall be
      converted into Common Units based on the fair market value of such
      Combined Interest as calculated pursuant to Section 13.3(a) and the
      Current Market Price of the Common Units as of the effective date of the
      departure of such Departing Partner. Any successor General Partner shall
      indemnify the Departing Partner as to all debts and liabilities of the
      Partnership arising on or after the date on which the Departing Partner
      becomes a Limited Partner. For purposes of this Agreement, conversion of a
      General Partner's Partnership Interest as a general partner in the
      Partnership to Common Units will be characterized as if such General
      Partner contributed its Partnership Interest to the Partnership in
      exchange for the newly-issued Common Units.

                                      -20-