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                                 Exhibit 10.21


                              FRONTIER CORPORATION

                      SUPPLEMENTAL MANAGEMENT PENSION PLAN

                      Amendment No. 1 to 1996 Restatement



     Pursuant to Article Six, the Plan is amended as follows:

     1.  Section 4.1(k) is amended, effective January 1, 1996, to clarify that
the five years of service requirement specified in Section 4.1(j) does not apply
to the 3 + 3 enhancement by deleting the current introductory clause of Section
4.1(k) and substituting in its place the following:

          for each Participant on the active payroll (or on the inactive payroll
          but receiving benefits under the Company's long term disability
          benefit plan) on August 16, 1995, the eligibility requirements for
          determining the Participant's entitlement to receive early or normal
          retirement benefits shall be reduced as follows:

     2.  Section 4.4 is amended by deleting the fourth sentence thereof and
substituting in its place the following:

          In the event no timely election is made or a timely election is not
          possible at the time benefits become payable (e.g., due to the death
          of a contingent annuitant or a change in marital status), the benefit
          to a single Participant will be paid in the form of a life annuity and
          the benefit to a married Participant not otherwise eligible to accrue
          a benefit under Section 4.2 (refer to Section 4.7 for these
          Participants) will be paid in the form of a joint and 50 percent
          spousal survivor annuity.  For purposes of this paragraph the survivor
          annuity shall provide that in the event the contingent annuitant
          predeceases the Participant, the Participant's benefit shall revert to
          the amount determined prior to the reduction for contingent annuitant
          benefits.

     3.  Section 4.5 is amended by deleting the first sentence thereof and
substituting in its place the following:

          If a Participant not otherwise eligible to accrue a benefit under
          Section 4.2 (refer to Section 4.7 for these Participants) dies while
          still employed

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          by a Participating Company and after becoming entitled to receive a
          vested benefit, the Participant's spouse, if surviving, shall be
          entitled to a monthly lifetime benefit equal to one-half of the
          benefit the Participant would have received under Section 4.1 had he
          or she elected a 50 percent contingent survivor annuity and retired on
          the first day of the month on or before the date of death.

     4.  Article Four is amended, effective as of August 20, 1997, by adding the
following new Section 4.7 to the end thereof:

     4.7  Notwithstanding the normal benefit payment provisions of Sections 4.4
          and 4.5, any Plan benefit payable to a Participant eligible to accrue
          a benefit under Section 4.2 on and after December 31, 1995 shall be
          subject to the following additional provisions:

          .  in addition to other forms of payment available to Participants
             generally, benefits to married Participants may, with the
             Committee's approval, be paid in the form of a joint and 100
             percent spousal survivor annuity. Under this form of benefit the
             surviving spouse shall receive, upon the death of the Participant,
             a benefit equal to 100 percent of the benefit paid to the
             Participant while both were living. The amount of this benefit
             shall be the straight life annuity calculated under Section 4.2
             (without taking into account the offset of the benefit payable from
             the Funded Plan) reduced pursuant to the actuarial assumptions used
             in the Funded Plan, provided that the straight life annuity shall
             not be reduced by more than 20 percent, and then offset by the
             benefit payable from the Funded Plan. For these purposes, if the
             Participant's contingent annuitant predeceases the Participant, the
             benefit thereafter payable to the Participant shall revert to the
             amount to which the Participant is entitled prior to reduction for
             the optional form of payment.
 
          .  in the event a married Participant dies prior to the commencement
             of benefits, the surviving spouse's benefit shall, with the
             Committee's approval, be 100 percent (in lieu of the 50% under
             Section 4.5) of the benefit the Participant would have received had
             the Participant elected the joint and 100 percent spousal survivor
             annuity and retired on the first day of the month on or before the
             date of death.
 
          .  if a married Participant fails to elect a form of benefit, or if
             the elected form of benefit is not appropriate as of the date of
             death, the benefit shall be paid in the form of a joint and 100
             percent spousal survivor annuity. For these purposes, if the
             Participant's contingent annuitant predeceases the Participant, the
             benefit thereafter payable to the Participant shall revert to the
             amount to which the Participant is entitled prior to reduction for
             the optional form of payment.
 
          .  In the discretion of the Committee, the value of the benefits
             payable under this Section 4.7 may be paid out in a lump sum or in
             another alternative form of benefit the Committee may elect.

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     IN WITNESS WHEREOF, the Company has caused this amendment to be executed by
its duly authorized officer this 20th day of August, 1997.

                                        FRONTIER CORPORATION


                                        By:  /s/ Josephine S. Trubek
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                                                 Josephine S. Trubek
                                                 Corporate Secretary

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