Exhibit 10.4

AMENDMENT NO. 1

          AMENDMENT NO. 1 (this “Amendment”), dated as of December 8, 2004, to
the credit agreement, dated as of November 16, 2004 (the “Credit Agreement”;
capitalized terms used herein and not defined herein shall have the meaning
assigned to such terms in the Credit Agreement), among Metrocall, Inc., a
Delaware corporation and Arch Wireless Operating Company, Inc., a Delaware
corporation, as borrowers (together, “Borrowers”), UBS AG, Stamford Brach, as
administrative agent (the “Administrative Agent”) and the Required Lenders.

W I T N E S S E T H:

          WHEREAS, Section 10.02(b) of the Credit Agreement permits the Credit
Agreement to be waived, amended, supplemented or modified from time to time with
the written consent of the Required Lenders;

          NOW, THEREFORE, in consideration of the foregoing, and for other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree as follows:

          SECTION ONE Amendments.

          (a) Section 1.01 of the Credit Agreement shall be amended by adding
thereto the following: “First Amendment Effective Date” shall mean the Effective
Date (as such term is defined in Amendment No. 1 to this Agreement).

          (b) The text and heading of Section 5.14 shall be replaced in its
entirety with the following: “Authorization of Collateral Agent to Terminate
Concentration Account. On or after the First Amendment Effective Date, the
Collateral Agent shall be authorized to terminate the Concentration Account
(which is entitled “Account Control Agreement”), dated as of the Closing Date,
among Metrocall, the Collateral Agent and UBS Financial Services Inc. in
accordance with the terms thereof; provided that (i) all securities in the
Concentration Account shall have been converted to cash such that at the time of
such termination, no asset other than cash shall be contained in the
Concentration Account and (ii) upon such termination, all of the cash in the
Concentration Account shall be used to make prepayments pursuant to
Section 2.10(a).”

          (c) Section 8.01 shall be amended by: (i) deleting the reference to
“5.14” in clause (d) thereof, (ii) adding, in clause (g)(i) thereof, the word
“United States” immediately prior to the word “Code” and (iii) in the
parenthetical phrase contained in Section 8.01(i), deleting (1) the entire text
of clause (y) appearing therein and (2) the reference to the character “(x)”
appearing therein.

 

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          SECTION TWO Conditions to Effectiveness. This Amendment shall become
effective as of the date (the “Effective Date”) when, and only when the
Administrative Agent shall have received counterparts of this Amendment executed
by each Borrower, the Administrative Agent and a number of Lenders sufficient to
constitute the Required Lenders. The effectiveness of this Amendment (other than
Sections Five, Six and Seven hereof) is conditioned upon the accuracy of the
representations and warranties set forth in Section Three hereof.

          SECTION THREE Representations and Warranties. In order to induce the
Required Lenders to enter into this Amendment, Borrowers, jointly and severally,
represent and warrant to each of the Lenders and the Administrative Agent that,
before and after giving effect to this Amendment, (a) no Default or Event of
Default has occurred and is continuing, (b) all of the representations and
warranties in the Credit Agreement are true and complete in all material
respects on and as of the date hereof as if made on the date hereof (or, if any
such representation or warranty is expressly stated to have been made as of a
specific date, as of such specific date) and (c) each stockholder of Metrocall
Public that shall have demanded appraisal rights in respect of any of its shares
of Metrocall Public has irrevocably withdrawn such demand for appraisal rights
in the manner required by applicable law for all of such stockholder’s shares of
Metrocall Public.

          SECTION FOUR Reference to and Effect on the Credit Agreement. On and
after the Effective Date, each reference in the Credit Agreement to “this
Agreement,” “hereunder,” “hereof” or words of like import referring the Credit
Agreement, and each reference in each Loan Document to “the Credit Agreement,”
“thereunder,” “thereof” or words of like import referring to the Credit
Agreement, shall mean and be a reference to the Credit Agreement, as amended by
this Amendment. The Credit Agreement and each of the other Loan Documents, as
specifically amended by this Amendment, are and shall continue to be in full
force and effect and are hereby in all respects ratified and confirmed. The
execution, delivery and effectiveness of this Amendment shall not, except as
expressly provided herein, operate as a waiver of any right, power or remedy of
any Lender or any Agent under any of the Loan Documents, nor constitute a waiver
of any provision of any of the Loan Documents.

          SECTION FIVE Costs and Expenses. Borrowers agree to pay all reasonable
costs and expenses of the Administrative Agent in connection with the
preparation, execution and delivery of this Amendment and the other instruments
and documents to be delivered hereunder, if any (including, without limitation,
the reasonable fees and expenses of Cahill Gordon & Reindel LLP, counsel to the
Administrative Agent) in accordance with the terms of Section 10.03(a)(i) of the
Credit Agreement.

          SECTION SIX Execution in Counterparts. This Amendment may be executed
in any number of counterparts and by different parties hereto in separate
counterparts, each of which when so executed shall be deemed to be an original
and all of which taken together shall constitute but one and the same agreement.
Delivery of an executed counterpart of a

 

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signature page to this Amendment by telecopier shall be effective as delivery of
a manually executed counterpart of this Amendment.

          SECTION SEVEN Governing Law. This Amendment shall be construed in
accordance with and governed by the law of the State of New York, without regard
to conflicts of law principles that would require the application of the laws of
another jurisdiction.

[Signature Pages Follow]

 

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            METROCALL, INC.
      By:   /s/ George Moratis         Name:   George Moratis        Title:  
Treasurer   

            ARCH WIRELESS OPERATING COMPANY, INC.
      By:   /s/ George Moratis         Name:   George Moratis        Title:  
Treasurer   

 

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            UBS AG, STAMFORD BRANCH, as Administrative Agent     By:   /s/
Wilifred V. Saint         Name:   Director        Title:   Banking Products
Services, US   

            By:   /s/ Doris Mesa         Name:   Associate Director       
Title:   Banking Products Services, US