<PAGE>



                                                                   EXHIBIT 10.55


                           SECOND AMENDMENT dated as of June 7, 2001 (this
                  "Amendment"), to the Amended and Restated Credit Agreement,
                  dated as of February 14, 2001, as amended and restated as of
                  March 30, 2001 (the "Credit Agreement"), as amended by the
                  First Amendment and Waiver dated as of May 8, 2001, among
                  ALAMOSA HOLDINGS, INC. ("Superholdings"), ALAMOSA (DELAWARE),
                  INC. ("Alamosa Delaware"), ALAMOSA HOLDINGS, LLC (the
                  "Borrower" and, together with Superholdings and Alamosa
                  Delaware, the "Alamosa Parties"), the Lenders party thereto
                  (the "Lenders"), EXPORT DEVELOPMENT CORPORATION, as
                  Co-Documentation Agent, FIRST UNION NATIONAL BANK, as
                  Documentation Agent, TORONTO DOMINION (TEXAS), INC., as
                  Syndication Agent, and CITICORP USA, INC., as Administrative
                  Agent and Collateral Agent (the "Agent").

                  WHEREAS the Alamosa Parties have requested that certain
provisions of the Credit Agreement be amended, in the manner provided for in
this Amendment, and the Required Lenders are willing to agree to such amendments
on the terms and conditions hereinafter set forth.


                  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. (a) Section 5.16 of the Credit Agreement is
hereby amended and restated in its entirety as follows:

                           "SECTION 5.16. Delivery of Revised Business Plans.
         Within 45 days after the effective date of the Second Amendment to this
         Agreement, dated as of June 7, 2001, among the Superholdings, Alamosa
         Delaware, the Borrower and the Required Lenders, Alamosa Delaware shall
         deliver to the Lenders an 8-year business plan of each of Alamosa
         Delaware and the Borrower, in form and substance satisfactory to the
         Required Lenders."

                  (b) Paragraph (d) of Article VII of the Credit Agreement is
hereby amended by replacing the word "or" immediately prior to the reference to
"5.15" with a comma and inserting the words "or 5.16" immediately prior to the
words "or in Article VI".

                  3. Effect of Amendment. Except as expressly set forth herein,
this Amendment shall not by implication or otherwise limit, impair, constitute a
waiver of, or otherwise affect the rights or remedies of the Lenders, the
Collateral Agent, the Syndication Agent, the Co-Documentation Agent, the
Documentation Agent or the Administrative Agent under the Credit Agreement or
any other Loan Document, and shall not alter, modify, amend or in any way affect
any of the terms, conditions, obligations, covenants or agreements contained in
the Credit Agreement or any other Loan Document, all of which are ratified and
affirmed in all respects and shall continue in full force and effect. Nothing
herein shall be deemed to entitle the Alamosa Parties to a consent to, or a
waiver, amendment, modification or other change of, any of the terms,
conditions, obligations, covenants or agreements contained in the Credit
Agreement or any other Loan Document in similar or different circumstances. This
Amendment


<PAGE>

                                                                               2


shall apply and be effective only with respect to the provisions of the Credit
Agreement set forth herein. After the date hereof, any reference to the Credit
Agreement shall mean the Credit Agreement as modified hereby. This Amendment
shall constitute a "Loan Document" for all purposes of the Credit Agreement and
the other Loan Documents.

                  4. Agreements of the Borrower. The Borrower hereby agrees that
from the date hereof until such date as Alamosa Delaware shall have complied
with the provisions of Section 5.16 of the Credit Agreement, as amended by this
Amendment, it shall not effect any Borrowing or deliver any Borrowing Request
under the Credit Agreement and any Borrowing Request delivered during such
period shall be ineffective.

                  5. Representations and Warranties. Each of the Alamosa Parties
hereby represents and warrants to the Agent and the Lenders as of the date
hereof as follows:

                  (a) Before and after giving effect to this Amendment, no
Default or Event of Default has occurred and is continuing.

                  (b) The execution, delivery and performance by the Alamosa
Parties 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
each of the Alamosa Parties, enforceable against it in accordance with its
terms, subject to applicable bankruptcy, insolvency, reorganization, moratorium
or other laws affecting creditors' rights generally and subject to general
principles of equity, regardless of whether considered in a proceeding in equity
or at law.

                  (c) All representations and warranties of the Alamosa Parties
contained in Article III of the Credit Agreement (other than representations or
warranties expressly made only on and as of the Restatement Effective Date) are
true and correct in all material respects as of the date hereof.

                  6. Effectiveness. This Amendment shall become effective on the
date when the Agent shall have received counterparts hereof duly executed and
delivered by the Alamosa Parties and the Required Lenders.

                  7. Expenses. The Alamosa Parties, jointly and severally, agree
to reimburse the 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 Agent.

                  8. GOVERNING LAW; COUNTERPARTS. (a) THIS AMENDMENT AND THE
RIGHTS AND OBLIGATIONS OF THE PARTIES HERETO SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

                  (b) This Amendment may be executed in any number of
counterparts and by different parties hereto on separate counterparts, each of
which when so executed and delivered shall be deemed an original, but all of
which together shall constitute a single instrument. Delivery of an executed
counterpart of a signature page of this Amendment by


<PAGE>



                                                                               3

facsimile transmission shall be as effective as delivery of a manually executed
counterpart hereof.




<PAGE>



                                                                               4

                  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.


                              ALAMOSA HOLDINGS, INC.,

                                  By /s/ Kendall W. Cowan
                                     ----------------------------------
                                     Name: Kendall W. Cowan
                                     Title: Chief Financial Officer


                              ALAMOSA (DELAWARE), INC.,

                                  By /s/ Kendall W. Cowan
                                     ----------------------------------
                                     Name: Kendall W. Cowan
                                     Title: Chief Financial Officer


                              ALAMOSA HOLDINGS, LLC,

                                  By /s/ Kendall W. Cowan
                                     ----------------------------------
                                     Name: Kendall W. Cowan
                                     Title: Chief Financial Officer


                              CITICORP USA, INC., individually and as
                              Administrative Agent,


                                  By /s/ John P. Judge
                                     ----------------------------------
                                     Name: John P. Judge
                                     Title: Vice President and Director


                              CITICORP NORTH AMERICA, INC.,


                                  By /s/ John P. Judge
                                     ----------------------------------
                                     Name: John P. Judge
                                     Title: Vice President  and Director



<PAGE>



                                                                               5


                                                           SIGNATURE PAGE to
                                                           SECOND AMENDMENT,
                                                   dated as of June 7, 2001,
                                                    to ALAMOSA HOLDINGS, LLC
                                       AMENDED AND RESTATED CREDIT AGREEMENT






                        To approve the Second Amendment:


                        Name of Institution:  THE BANK OF NOVA SCOTIA
                                              -----------------------

                                                By  /s/ P.A. Weissenberger
                                                    ---------------------------
                                                    Name: P.A. Weissenberger
                                                    Title: Authorized Signatory




<PAGE>



                                                                               6


                                                               SIGNATURE PAGE to
                                                               SECOND AMENDMENT,
                                                       dated as of June 7, 2001,
                                                        to ALAMOSA HOLDINGS, LLC
                                           AMENDED AND RESTATED CREDIT AGREEMENT






                        To approve the Second Amendment:


                        Name of Institution: EXPORT DEVELOPMENT CORPORATION
                                             ------------------------------

                                                  By  /s/ Luisa Rebolledo
                                                      --------------------------
                                                      Name: Luisa Rebolledo
                                                      Title:  Loan Asset Manager


                                                  By  /s/ Sadig Raza
                                                      --------------------------
                                                       Name: Sadig Raza
                                                       Title: Loan Asset Manager


<PAGE>



                                                                               7

                                                               SIGNATURE PAGE to
                                                               SECOND AMENDMENT,
                                                       dated as of June 7, 2001,
                                                        to ALAMOSA HOLDINGS, LLC
                                           AMENDED AND RESTATED CREDIT AGREEMENT






                        To approve the Second Amendment:


                        Name of Institution: TORONTO DOMINION (TEXAS), INC.
                                             ------------------------------

                                                  By  /s/ Alva J. Jones
                                                      ------------------------
                                                      Name: Alva J. Jones
                                                      Title: Vice President




<PAGE>



                                                                               8

                                                              SIGNATURE PAGE to
                                                              SECOND AMENDMENT,
                                                      dated as of June 7, 2001,
                                                       to ALAMOSA HOLDINGS, LLC
                                          AMENDED AND RESTATED CREDIT AGREEMENT






                       To approve the Second Amendment:


                       Name of Institution: GENERAL ELECTRIC CAPITAL CORPORATION
                                            ------------------------------------

                                                  By  /s/ Brian P. Ward
                                                      ------------------------
                                                      Name: Brian P. Ward
                                                      Title:  Manager-Operations



<PAGE>



                                                                               9

                                                              SIGNATURE PAGE to
                                                              SECOND AMENDMENT,
                                                      dated as of June 7, 2001,
                                                       to ALAMOSA HOLDINGS, LLC
                                          AMENDED AND RESTATED CREDIT AGREEMENT






                        To approve the Second Amendment:


                        Name of Institution: COBANK, ACB
                                             -----------

                                                By  /s/ Anita Youngblut
                                                    ---------------------------
                                                    Name: Anita Youngblut
                                                    Title:  Vice President




<PAGE>


                                                                              10



                                                             SIGNATURE PAGE to
                                                             SECOND AMENDMENT,
                                                     dated as of June 7, 2001,
                                                      to ALAMOSA HOLDINGS, LLC
                                         AMENDED AND RESTATED CREDIT AGREEMENT






                        To approve the Second Amendment:


                        Name of Institution: FIRST UNION NATIONAL BANK
                                             -------------------------

                                             By  /s/ Stephen G. Locke
                                                 -------------------------------
                                                 Name: Stephen G. Locke
                                                 Title: Assistant Vice President