Document:

<PAGE>

                                                                Exhibit 10.22.11

     TENTH AMENDMENT, dated as of July 17, 2000 (this "Amendment"), to the
                                                       ---------
Credit Agreement, dated as of July 17, 1998 (as amended, supplemented or
otherwise modified from time to time, the "Credit Agreement"), among TELECORP
                                           ----------------
PCS, INC., a corporation organized under the laws of the State of Delaware (the
"Borrower"), the several banks and other financial institutions and entities
 --------
from time to time parties thereto (the "Lenders"), and THE CHASE MANHATTAN BANK,
                                        -------
as administrative agent (the "Administrative Agent") for the Lenders.
                              --------------------

          WHEREAS, pursuant to the Credit Agreement, the Lenders have agreed to
make certain loans to the Borrower; and

          WHEREAS the Borrower has requested that certain provisions of the
Credit Agreement be modified in the manner provided for in this Amendment, and
the Lenders are willing to agree to such modifications as provided for in this
Amendment.

          NOW, THEREFORE, the parties hereto hereby agree as follows:

          1.  Defined Terms.  Capitalized terms used and not defined herein
              --------------
shall have the meanings given to them in the Credit Agreement, as amended
hereby.

          2.  Amendments to the Credit Agreement.
              -----------------------------------

          (a)  Section 1.01 of the Credit Agreement is hereby amended by:

          (i) deleting "and (b)" in the definition of "Applicable Margin" and
     substituting the following therefor:

               ", (b) with respect to any Tranche C Term Loan, the applicable
          Tranche C Rate and (c)"
<PAGE>

          (ii) deleting the definition of "Class" and substituting the following
     therefor:

               "'Class', when used in reference to any Loan or Borrowing, refers
                 -----
          to whether such Loan, or the Loans comprising such Borrowing, are
          Revolving Loans, Tranche A Term Loans, Tranche B Term Loans or Tranche
          C Term Loans and, when used in reference to any Commitment, refers to
          whether such Commitment is a Revolving Commitment, Tranche A
          Commitment, Tranche B Commitment or Tranche C Commitment."

          (iii) deleting the definition of "Term Loans" and substituting the
following therefor:

               "'Term Loans' means Tranche A Term Loans, Tranche B Term Loans
                 ----------
          and Tranche C Term Loans."

          (iv) adding the following definitions in their appropriate
alphabetical order:

               "'Tranche C Availability Period' means the period from and
                 -----------------------------
          including May 5, 2000 to but excluding the earlier of May 5, 2002 and
          the date of termination of the Tranche C Commitments.

               'Tranche C Commitment' means, with respect to each Lender, the
                --------------------
          commitment, if any, of such Lender to make Tranche C Term Loans
          hereunder, expressed as an amount representing the maximum principal
          amount of the Tranche C Term Loans to be made by such Lender
          hereunder, as such commitment may be (a) reduced from time to time
          pursuant to Section 2.06 and (b) reduced or increased from time to
          time pursuant to assignments by or to such Lender pursuant to Section
          9.04.  The initial amount of each Lender's Tranche C Commitment is set
          forth on Schedule 2.01(a), or in the Assignment and Acceptance
          pursuant to which such Lender shall have assumed its Tranche C
          Commitment, as applicable.  The initial aggregate amount of the
          Lenders' Tranche C Commitments is $35,000,000.
<PAGE>

               'Tranche C Lender' means a Lender with a Tranche C Commitment or
                ----------------
          an outstanding Tranche C Term Loan.

               'Tranche C Maturity Date' means May 17, 2009.
                -----------------------

               'Tranche C Rate' means, with respect to any Tranche C Term Loan
                --------------
          (a) 2.00% per annum, in the case of an ABR Loan, and (b) 3.00% per
          annum, in the case of a Eurodollar Loan

               'Tranche C Term Loan' means a Loan made pursuant to clause (c) of
                -------------------
          Section 2.01."

          (v) inserting ", Schedule 2.01(a)" in the definition of "Lenders"
     immediately after "Schedule 2.01":

          (b)  Section 2.01 of the Credit Agreement is hereby amended by
deleting "and (c)" therefrom and substituting the following therefor:

               ", (c) to make Tranche C Term Loans to the Borrower during the
          Tranche C Availability Period in an aggregate principal amount not
          exceeding its Tranche C Commitment and (d)"

          (c)  Section 2.02(d) is hereby amended by deleting "or Tranche B
Maturity Date" therefrom and inserting therefor the following:

          ", Tranche B Maturity Date or Tranche C Maturity Date"

          (d)  Clause (i) of Section 2.03 of the Credit Agreement is hereby
amended by deleting therefrom "or Tranche B Term Borrowing" and substituting
therefor the following:

          ", Tranche B Term Borrowing or Tranche C Term Borrowing"
<PAGE>

          (e)  Section 2.06(a) of the Credit Agreement is hereby amended by
deleting "and (iii)" therefrom and substituting therefor the following:

          ", (iii) the Tranche C Commitments shall terminate at 5:00 p.m. New
     York City time on the last day of the Tranche C Availability Period and
     (iv)"

          (f)  Section 2.08 is hereby amended by deleting clauses (d), (e) and
(f) thereof and substituting the following therefor:

               (d)  To the extent not previously paid, (i) all Tranche A Term
          Loans shall be due and payable on the Tranche A Maturity Date, (ii)
          all Tranche B Term Loans shall be due and payable on the Tranche B
          Maturity Date and (iii) all Tranche C Term Loans shall be due and
          payable on the Tranche C Maturity Date.

               (e)  If the initial aggregate amount of the Lenders' Term
          Commitments of any Class exceeds the aggregate principal amount of
          Term Loans of such Class that are made (i) during the Tranche A
          Availability Period, in the case of the Tranche A Term Loans, (ii) on
          the Effective Date, in the case of the Tranche B Term Loans or (iii)
          during the Tranche C Availability Period, in the case of Tranche C
          Term Loans, then the scheduled repayments of Term Borrowings of such
          Class to be made pursuant to this Section shall be reduced ratably by
          an aggregate amount equal to such excess.  Any prepayment of a Term
          Borrowing of any Class shall be applied to reduce the subsequent
          scheduled repayments of the Term Borrowings of such Class to be made
          pursuant to this Section ratably.

               (f)  Prior to any repayment of any Term Borrowings of any Class
          hereunder, the Borrower shall select the Borrowing or Borrowings of
          the applicable Class to be repaid and shall notify the Administrative
          Agent by telephone (confirmed by telecopy) of such selection not later
          than 11:00 a.m., New York City time, three Business Days
<PAGE>

          before the scheduled date of such repayment; provided that each
                                                       --------
          repayment of Term Borrowings of any Class shall be applied to repay
          any outstanding ABR Term Borrowings of such Class before any other
          Borrowings of such Class. Each repayment of a Borrowing shall be
          applied ratably to the Loans included in the repaid Borrowing.
          Repayments of Term Borrowings shall be accompanied by accrued interest
          on the amount repaid."

          (g)  Section 2.09 of the Credit Agreement is hereby deleted in its
entirety and the following substituted therefor:

               "SECTION 2.09.  Prepayment of Loans.  (a)  The Borrower shall
                               --------------------
          have the right at any time and from time to time to prepay any
          Borrowing in whole or in part, subject to the requirements of this
          Section.

               (b)  In the event and on each occasion that any Net Proceeds are
          received by or on behalf of the Borrower or any Subsidiary in respect
          of any Prepayment Event, promptly and in any event not later than the
          Business Day after such Net Proceeds are received, the Borrower shall
          prepay Term Borrowings and the Revolving Commitments and the unused
          Tranche A Commitments and Tranche C Commitments shall be automatically
          and permanently reduced in an aggregate amount (to be applied ratably
          among the unused Tranche A Commitments, the Tranche A Term Loans, the
          Tranche B Term Loans, the unused Tranche C Commitments, the Tranche C
          Term Loans and the Revolving Commitments based on their then
          respective amounts) equal to (i) in the case of an event described in
          clause (c) of the definition of "Prepayment Event", 50% of such Net
          Proceeds and (ii) in the case of an event described in any other
          clause of the definition of "Prepayment Event", 100% of such Net
          Proceeds.

               (c)  Following the end of the fiscal year of the Borrower ending
          December 31, 2001 and
<PAGE>

          following the end of each subsequent fiscal year, the Borrower shall
          prepay Term Borrowings and the Revolving Commitments and the unused
          Tranche A Commitments and Tranche C Commitments shall be automatically
          and permanently reduced in an aggregate amount (to be applied ratably
          among the unused Tranche A Commitments, the Tranche A Term Loans, the
          Tranche B Term Loans, the unused Tranche C Commitments, the Tranche C
          Term Loans and the Revolving Commitments based on their then
          respective amounts) equal to 50% of Excess Cash Flow for such fiscal
          year. Each prepayment pursuant to this paragraph shall be made on or
          before the third Business Day after the date on which financial
          statements are delivered (or, if earlier, required to be delivered)
          pursuant to Section 5.01(a) with respect to the fiscal year for which
          Excess Cash Flow is being calculated.

               (d)  Prior to any optional or mandatory prepayment of Borrowings
          hereunder, the Borrower shall select the Borrowing or Borrowings to be
          prepaid and shall specify such selection in the notice of such
          prepayment pursuant to paragraph (e) of this Section; provided that
                                                                --------
          (i) all prepayments shall be applied ratably among the unused Tranche
          A Commitments, the Tranche A Term Loans, the Tranche B Term Loans, the
          unused Tranche C Commitments, the Tranche C Term Loans and the
          Revolving Commitments and (ii) each prepayment of Borrowings of any
          Class shall be applied to prepay ABR Borrowings of such Class before
          any other Borrowings of such Class.  Any amounts remaining after such
          application shall, at the option of the Borrower, be applied to prepay
          Eurodollar Borrowings immediately and/or shall be deposited in the
          Prepayment Account (as defined below).  The Administrative Agent shall
          apply any cash deposited in the Prepayment Account to prepay
          Eurodollar Borrowings on the last day of their respective Interest
          Periods (or, at the direction of the Borrower, on any earlier date)
          until all outstanding Eurodollar Borrowings have been prepaid or until
          all the allocable cash on deposit with respect to such
<PAGE>

          Loans has been exhausted. For purposes of this Agreement, the term
          "Prepayment Account" shall mean an account established by the Borrower
          with the Administrative Agent and over which the Administrative Agent
          shall have exclusive dominion and control, including the exclusive
          right of withdrawal for application in accordance with this paragraph
          (d). The Administrative Agent will, at the request of the Borrower,
          invest amounts on deposit in the Prepayment Account in Permitted
          Investments that mature prior to the last day of the applicable
          Interest Periods of the Eurodollar Borrowings to be prepaid; provided,
          however, that (i) the Administrative Agent shall not be required to
          make any investment that, in its sole judgment, would require or cause
          the Administrative Agent to be in, or would result in any, violation
          of any law, statute, rule or regulation and (ii) the Administrative
          Agent shall have no obligation to invest amounts on deposit in the
          Prepayment Account if a Default or Event of Default shall have
          occurred and be continuing. The Borrower shall indemnify the
          Administrative Agent for any losses relating to the investments so
          that the amount available to prepay Eurodollar Borrowings on the last
          day of the applicable Interest Period is not less than the amount that
          would have been available had no investments been made pursuant
          thereto. Other than any interest earned on such investments, the
          Prepayment Account shall not bear interest. Interest or profits, if
          any, on such investments shall be deposited in the Prepayment Account
          and reinvested and disbursed as specified above. If the maturity of
          the Loans has been accelerated pursuant to Article VII, the
          Administrative Agent may, in its sole discretion, apply all amounts on
          deposit in the Prepayment Account to satisfy any of the Obligations.
          The Borrower hereby grants to the Administrative Agent, for its
          benefit and the benefit of the Issuing Bank and the Lenders, a
          security interest in the Prepayment Account to secure the Obligations.
          In the event of any optional or mandatory prepayment of Term
          Borrowings or
<PAGE>

          reduction of Tranche A Commitments and Tranche C Commitments made at a
          time when Term Borrowings or unused Commitments of more than one Class
          remain outstanding, the Borrower shall select Term Borrowings to be
          prepaid and Tranche A Commitments and Tranche C Commitments to be
          reduced so that the aggregate amount of such prepayment is allocated
          between the unused Tranche A Commitments, the Tranche A Term
          Borrowings, the Tranche B Term Borrowings, the unused Tranche C
          Commitments and Tranche C Term Borrowings pro rata based on the
          aggregate principal amount of outstanding Borrowings or unused
          Commitments of each such Class; provided that any Tranche B Lender or
                                          --------
          Tranche C Lender may elect, by notice to the Administrative Agent by
          telephone (confirmed by telecopy) at least one Business Day prior to
          the prepayment date, to decline all or any portion of any prepayment
          of its Tranche B Term Loans or Tranche C Term Loans pursuant to this
          Section (other than an optional prepayment pursuant to paragraph (a)
          of this Section, which may not be declined), in which case the Net
          Proceeds or Excess Cash Flow that would have been applied to prepay
          Tranche B Term Loans or Tranche C Term Loans or to reduce the unused
          Tranche C Commitments but were so declined shall be applied to prepay
          Tranche A Term Loans and to reduce the Revolving Commitments and the
          unused Tranche A Commitments on a pro rata basis based on their then
          respective amounts.

               (e)  The amount of any optional or mandatory prepayments
          allocated to Term Loans shall be applied pro rata to reduce the
          principal amount of the then remaining amortization installments
          applicable to such Loans set forth in Section 2.08.  The amount of any
          optional or mandatory commitment reductions allocated to the Revolving
          Commitments, the unused Tranche A Commitments or the unused Tranche C
          Commitments shall be applied pro rata to reduce the principal amount
          of the then remaining reductions applicable to such Commitments set
          forth in Section 2.08.  Any reduction of the Revolving Commitments
          shall be
<PAGE>

          accompanied by prepayment of Revolving Loans to the extent the
          aggregate amount of such loans outstanding exceeds the total amount of
          the Revolving Commitments as so reduced.

               (f)  The Borrower shall notify the Administrative Agent by
          telephone (confirmed by telecopy) of any prepayment hereunder (i) in
          the case of prepayment of a Eurodollar Revolving Borrowing, not later
          than 11:00 a.m., New York City time, three Business Days before the
          date of prepayment, (ii) in the case of prepayment of an ABR Revolving
          Borrowing, not later than 11:00 a.m., New York City time, one Business
          Day before the date of prepayment.  Each such notice shall be
          irrevocable and shall specify the prepayment date, the principal
          amount of each Borrowing or portion thereof to be prepaid and, in the
          case of a mandatory prepayment, a reasonably detailed calculation of
          the amount of such prepayment; provided that, if a notice of optional
                                         --------
          prepayment is given in connection with a conditional notice of
          termination of the Revolving Commitments as contemplated by Section
          2.08, then such notice of prepayment may be revoked if such notice of
          termination is revoked in accordance with Section 2.08.  Promptly
          following receipt of any such notice, the Administrative Agent shall
          advise the Lenders of the contents thereof.  Each partial prepayment
          of any Borrowing shall be in an amount that would be permitted in the
          case of an advance of a Borrowing of the same Type as provided in
          Section 2.02, except as necessary to apply fully the required amount
          of a mandatory prepayment.  Each prepayment of a Borrowing shall be
          applied ratably to the Loans included in the prepaid Borrowing.
          Prepayments shall be accompanied by accrued interest to the extent
          required by Section 2.13."

          (h)  Section 2.16(c) is hereby deleted in its entirety and the
following substituted therefor:

               "(c)  If any Lender shall, by exercising any right of set off or
          counterclaim or otherwise,
<PAGE>

          obtain payment in respect of any Loan or Loans or L/C Disbursement as
          a result of which the unpaid principal portion of its Tranche A Term
          Loans, Tranche B Term Loans, Tranche C Term Loans or Revolving Loans
          or participations in L/C Disbursements shall be proportionately less
          than the unpaid principal portion of the Tranche A Term Loans, Tranche
          B Term Loans, Tranche C Term Loans or Revolving Loans and
          participations in L/C Disbursements of any other Lender, it shall be
          deemed simultaneously to have purchased from such other Lender at face
          value, and shall promptly pay to such other Lender the purchase price
          for, a participation in the Tranche A Term Loans, Tranche B Term
          Loans, Tranche C Term Loans or Revolving Loans or L/C Exposure, as the
          case may be, of such other Lender, so that the aggregate unpaid
          principal amount of the Tranche A Term Loans, Tranche B Term Loans,
          Tranche C Term Loans and Revolving Loans and participations in Tranche
          A Term Loans, Tranche B Term Loans, Tranche C Term Loans and Revolving
          Loans and L/C Exposure held by each Lender shall be in the same
          proportion to the aggregate unpaid principal amount of all Tranche A
          Term Loans, Tranche B Term Loans, Tranche C Term Loans and Revolving
          Loans and L/C Exposure then outstanding as the principal amount of its
          Tranche A Term Loans, Tranche B Term Loans, Tranche C Term Loans and
          Revolving Loans prior to such exercise of any right of setoff or
          counterclaim or other event was to the principal amount of all Tranche
          A Term Loans, Tranche B Term Loans, Tranche C Term Loans and Revolving
          Loans and L/C Exposure outstanding prior to such exercise of any right
          of setoff or counterclaim or other event; provided that (i) if any
                                                    --------
          such participations are purchased and all or any portion of the
          payment giving rise thereto is recovered, such participations shall be
          rescinded and the purchase price restored to the extent of such
          recovery, without interest, and (ii) the provisions of this paragraph
          shall not be construed to apply to any payment made by the Borrower
          pursuant to and in accordance with the express terms of this Agreement
          or any payment
<PAGE>

          obtained by a Lender as consideration for the assignment of or sale of
          a participation in any of its Loans to any assignee or participant,
          other than to the Borrower or any Subsidiary or Affiliate thereof (as
          to which the provisions of this paragraph shall apply). The Borrower
          consents to the foregoing and agrees, to the extent it may effectively
          do so under applicable law, that any Lender acquiring a participation
          pursuant to the foregoing arrangements may exercise against the
          Borrower rights of setoff and counterclaim with respect to such
          participation as fully as if such Lender were a direct creditor of the
          Borrower in the amount of such participation.

          (i)  Section 2.18 is amended by inserting at the end thereof the
following:

          "The Tranche C Term Loans are Expansion Term Loans."

          (j)  Schedule 2.01(a) attached as Annex A hereto is hereby inserted in
the Credit Agreement between Schedule 2.01 and Schedule 3.05.

          (k)  Section 9.02(b) of the Credit Agreement is amended by deleting
clause (ix) of the first proviso therein and replacing such clause with "(ix)
change the rights of the Tranche B Lenders or Tranche C Lenders, as applicable,
to decline mandatory prepayments as provided in Section 2.09, without the
written consent of Tranche B Lenders or Tranche C Lenders, as applicable, in
each case holding a majority of the outstanding Tranche B Loans or Tranche C
Loans and unused Tranche C Commitments, as applicable".

          (l)  Section 9.02(b) of the Credit Agreement is amended by deleting
clause (B) of the final proviso therein and replacing such clause with "(B) any
waiver, amendment or modification of this Agreement that by its terms affects
the rights or duties under this Agreement of the Revolving Lenders (but not the
Tranche A Lenders, the Tranche B Lenders or the Tranche C Lenders), the Tranche
A Lenders (but not the Revolving Lenders, the Tranche B Lenders or
<PAGE>

the Tranche C Lenders), the Tranche B Lenders (but not the Revolving Lenders,
the Tranche A Lenders or the Tranche C Lenders) or the Tranche C Lenders (but
not the Revolving Lenders, the Tranche A Lenders or the Tranche B Lenders) may
be effected by an agreement or agreements in writing entered into by the
Borrower and the requisite percentage in interest of the affected Class of
Lenders".

          3.  No Other Amendments; Confirmation.  Except as expressly amended,
              ----------------------------------
waived, modified and supplemented hereby, the provisions of the Credit Agreement
are and shall remain in full force and effect.

          4.  Representations and Warranties.  The Borrower hereby represents
              -------------------------------
and warrants to the Administrative Agent and the Lenders as of the date hereof:

          (a) No Default or Event of Default has occurred and is continuing.

          (b) The execution, delivery and performance by the Borrower of this
     Amendment have been duly authorized by all necessary corporate and other
     action and do not and will not require any registration with, consent or
     approval of, notice to or action by, any person (including any governmental
     agency) in order to be effective and enforceable.  The Credit Agreement as
     amended by this Amendment constitutes the legal, valid and binding
     obligation of the Borrower, enforceable against it in accordance with its
     terms, subject only to the operation of the Bankruptcy Code and other
     similar statutes for the benefit of debtors generally and to the
     application of general equitable principles.

          (c) All representations and warranties of the Borrower contained in
     the Credit Agreement (other than representations or warranties expressly
     made only on and as of the Effective Date) are true and correct as of the
     date hereof.

          5.  Effectiveness.  This Amendment shall become effective only upon
              --------------
the satisfaction in full of the following conditions precedent:
<PAGE>

          (a) The Administrative Agent shall have received counterparts hereof,
     duly executed and delivered by the Borrower and Lucent; and

          (b) The Administrative Agent shall have received such opinions and
     certificates from the Borrower and its counsel as it may reasonably request
     in form reasonably satisfactory to its counsel.

          6.  Expenses.  The Borrower agrees to reimburse the Administrative
              ---------
Agent for its out-of-pocket expenses in connection with this Amendment,
including the reasonable fees, charges and disbursements of Cravath, Swaine &
Moore, counsel for the Administrative Agent.

          7.  Governing Law; Counterparts.  (a) This Amendment and the rights
              ----------------------------
and obligations of the parties hereto shall be governed by, and construed and
interpreted in accordance with, the laws of the State of New York.

          (b) This Amendment may be executed by one or more of the parties to
this Amendment on any number of separate counterparts, and all of said
counterparts taken together shall be deemed to constitute one and the same
instrument.  This Amendment may be delivered by facsimile transmission of the
relevant signature pages hereof.
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be duly executed and delivered by their respective proper and duly authorized
officers as of the day and year first above written.

                                        TELECORP PCS, INC.,

                                        by /s/ Thomas H. Sullivan
                                           -------------------------
                                              Name: /s/ Thomas H. Sullivan
                                              Title: Executive Vice President
                                                     and Chief Financial Officer

                                        LUCENT TECHNOLOGIES, INC.,

                                        by /s/ Lucent Technologies Inc.
                                           ----------------------------
                                              Name:
                                              Title:
<PAGE>

                               ANNEX A

                                                            SCHEDULE 2.01(a)

                               TRANCHE C COMMITMENTS

Lender(s)                                 Tranche C Commitment
---------                                 --------------------

Lucent Technologies, Inc.                    $35,000,000
                                              ----------

Total                                        $35,000,000<PAGE>

                                                                Exhibit 10.22.12

                              ELEVENTH AMENDMENT, dated as of June 28, 2000
                         (this "Amendment"), to the Credit Agreement, dated as
                                ---------
                         of July 17, 1998 (as amended, supplemented or otherwise
                         modified from time to time, the "Credit Agreement"),
                                                          ----------------
                         among TELECORP PCS, INC., a corporation organized under
                         the laws of the State of Delaware (the "Borrower"), the
                                                                 --------
                         several banks and other financial institutions and
                         entities from time to time parties thereto (the
                         "Lenders"), and THE CHASE MANHATTAN BANK, as
                          -------
                         administrative agent (the "Administrative Agent") for
                                                    --------------------
                         the Lenders.

          WHEREAS, pursuant to the Credit Agreement, the Lenders have agreed to
make certain loans to the Borrower; and

          WHEREAS, the Borrower has requested that certain provisions of the
Credit Agreement be modified in the manner provided for in this Amendment, and
the Lenders are willing to agree to such modifications as provided for in this
Amendment.

          NOW, THEREFORE, the parties hereto hereby agree as follows:

          1.   Defined Terms.  Capitalized terms used and not defined herein
               -------------
shall have the meanings given to them in the Credit Agreement, as amended
hereby.

          2.   Amendment to the Credit Agreement; Acknowledgement of Terms.
               -----------------------------------------------------------
Section 6.01(a)(ii) of the Credit Agreement is hereby amended by deleting
"$375,000,000" and inserting in its place "$875,000,000".  The Required Lenders
hereby agree that the terms of the Subordinated Debt substantially the same as
those described in the offering circular attached hereto as Exhibit A (but in
any amount yielding gross proceeds no greater than $500,000,000) are reasonably
acceptable under the definition of "Subordinated Debt" in the Credit Agreement.

          3.   No Other Amendments; Confirmation.  Except as expressly amended,
               ---------------------------------
waived, modified and supplemented hereby, the provisions of the Credit Agreement
are and shall remain in full force and effect.

          4.   Representations and Warranties.  The Borrower hereby represents
               ------------------------------
and warrants to the Administrative Agent and the Lenders as of the date hereof:

          (a)  No Default or Event of Default has occurred and is continuing.

          (b)  The execution, delivery and performance by the Borrower of this
     Amendment have been duly authorized by all necessary corporate and other
     action and do not and will not require any registration with, consent or
     approval of, notice to action
<PAGE>

     by, any person (including any governmental agency) in order to be effective
     and enforceable. The Credit Agreement as amended by this Amendment
     constitutes the legal, valid and binding obligation of the Borrower,
     enforceable against it in accordance with its terms, subject only to the
     operation of the Bankruptcy Code and other similar statutes for the benefit
     of debtors generally and to the application of general equitable
     principles.

          (c)  All representations and warranties of the Borrower contained in
     the Credit Agreement (other than representations or warranties expressly
     made only on and as of the Effective Date) are true and correct as of the
     date hereof.

          5.   Effectiveness.  This Amendment shall become effective on the date
               -------------
(the "Amendment Effective Date") on which the Administrative Agent shall have
      ------------------------
received counterparts hereof, duly executed and delivered by the Borrower, and
the Required Lenders; provided, that this Amendment shall not become effective
                      --------
unless the Amendment Effective Date shall have occurred on or before July 7,
2000.

          6.   Expenses.  The Borrower agrees to reimburse the Administrative
               --------
Agent for its out-of-pocket expenses in connection with this Amendment,
including the reasonable fees, charges and disbursements of Cravath, Swaine &
Moore, counsel for the Administrative Agent.

          7.   Governing Law; Counterparts.  (a)  This Amendment and the rights
               ---------------------------
and obligations of the parties hereto shall be governed by, and construed and
interpreted in accordance with, the laws of the State of New York.

          (b)  This Amendment may be executed by one or more of the parties to
this Amendment on any number of separate counterparts, and all of said
counterparts taken together shall be deemed to constitute one and the same
instrument.

                                      -2-
<PAGE>

This Amendment may be delivered by facsimile transmission of the relevant
signature pages hereof.

          IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be duly executed and delivered by their respective proper and duly authorized
officers as of the day and year first above written.

                                   TELECORP PCS, INC.,

                                   by: /s/ Thomas H. Sullivan
                                       ----------------------
                                       Name:
                                       Title:

                                   THE CHASE MANHATTAN BANK,

                                   by: /s/ William E. Rottino
                                       ----------------------
                                       Name:  William E. Rottino
                                       Title:  Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    THE CHASE MANHATTAN BANK

                                        by: /s/ William E. Rottino
                                            ----------------------
                                            Name:  William E. Rottino
                                            Title:  Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    ALLFIRST BANK

                                        by: /s/ W. Blake Hampson
                                            --------------------
                                            Name:  W. Blake Hampson
                                            Title:  Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    THE BANK OF NEW YORK

                                        by: /s/ Gerry Granovsky
                                            -------------------
                                            Name:  Gerry Granovsky
                                            Title:  Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    BANKERS TRUST CO.

                                        by: /s/ Bankers Trust Co.
                                            ---------------------
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    CIBC INC.

                                        by: /s/ George Knight
                                            -----------------
                                            Name:  George Knight
                                            Title: Managing Director
                                                   CIBC World Markets Corp.
                                                   As Agent
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    THE CIT GROUP/EQUIPMENT FINANCING

                                        by: /s/ Daniel E. A. Nichols
                                            ------------------------
                                            Name:  Daniel E. A. Nichols
                                            Title:  Assistant Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    FLEET NATIONAL BANK

                                        by: /s/ Suzanne M. MacKay
                                            ---------------------
                                            Name:  Suzanne M. MacKay
                                            Title:  Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    GENERAL ELECTRIC CAPITAL CORPORATION

                                        by: /s/ Brian P. Ward
                                            -----------------
                                            Name:  Brian P. Ward
                                            Title:  Manager - Operations
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    LEHMAN COMMERCIAL PAPER INC.

                                        by: /s/ Michele Swanson
                                            -------------------
                                            Name:  Michele Swanson
                                            Title:  Authorized Signatory
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    MORGAN GUARANTY TRUST COMPANY OF NEW
                                        YORK

                                        by: /s/ Colleen Galle
                                            -----------------
                                            Name:  Colleen Galle
                                            Title:  Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    NATIONAL WESTMINSTER BANK, PLC

                                        By: NatWest Capital Markets Limited, its
                                            Agent

                                        By: Greenwich Capital Markets, Inc., its
                                            Agent

                                            by: Ann Marie Petrovcik
                                                -------------------
                                                Name:  Ann Marie Petrovcik
                                                Title:  Senior Vice President
<PAGE>

(Signature page to the Eleventh Amendment, dated as of June 28, 2000, to the
Credit Agreement dated as of July 17, 1998, among TeleCorp PCS, Inc., the
lenders party thereto and The Chase Manhattan Bank, as Administrative Agent)

               Legal Name of Lender:    TORONTO DOMINION (TEXAS) INC.

                                        by: /s/ Lynn Chasin
                                            ---------------
                                            Name:  Lynn Chasin
                                            Title:  Vice President

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}]]