<PAGE>   1
                                                                   EXHIBIT 10.37




                                                                    CONFIDENTIAL

                                                             |__| Kelly's Copy
                                                             |__| Company's Copy
                               FIRST AMENDMENT TO
                           CHANGE OF CONTROL AGREEMENT

To VINCENT D. KELLY:

         By signing below, you agree to this First Amendment (the "Amendment")
to your Change of Control Agreement with Metrocall, Inc. (the "Company") dated
as of May 15, 1996 (the "Change of Control Agreement"). This Amendment is
effective as of April 1, 2001.

        1.      Section 1(b) is hereby deleted in its entirety and replaced with
                the following:

                "(b)    CHANGE OF CONTROL. For purposes of this Agreement, the
                        term "Change in Control" means the first to occur of the
                        following:

                        (i) any Person or group of Persons acting in concert, in
                        a transaction or a series of transactions, is or becomes
                        the Beneficial Owner, directly or indirectly, of
                        securities of the Company representing more than 50% of
                        the combined voting power of the Company's then
                        outstanding securities that have the right to vote for
                        the election of directors generally (not including in
                        such securities beneficially owned by such Person any
                        securities acquired directly from or received through an
                        exchange offer with the Company), other than any Person
                        who becomes such a Beneficial Owner in connection with a
                        transaction described in clause (i) of Section 3.2(3);
                        or

                        (ii) the following individuals cease for any reason to
                        constitute 66 2/3% of the directors of the Company then
                        serving: individuals who on the effective date hereof
                        constitute the Board, and any new director whose
                        appointment or election by the Board or nomination for
                        election by the Company's stockholders was approved or
                        recommended by at least two-thirds (2/3) of the
                        directors then still in office who either were directors
                        on the date hereof or whose appointment, election or
                        nomination for election was previously so approved or
                        recommended (other than a new director whose initial
                        assumption of office is in connection with an actual or
                        threatened election contest, including but not limited
                        to a consent solicitation, relating to the election of
                        directors of the Company); or

                        (iii) there is consummated a merger, consolidation or
                        other business combination (including an exchange of
                        securities with the security holder's of a corporation
                        that is a constituent in such business combination) of
                        the Company or any direct or indirect subsidiary of the
                        Company with any other corporation, other than (i) a
                        merger, consolidation or business combination which
                        would result in the voting

<PAGE>   2

                        securities of the Company outstanding immediately prior
                        to such merger, consolidation or business combination
                        continuing to represent at least a majority of the
                        combined voting power of the securities having the right
                        to vote for the election of directors generally of the
                        Company or the surviving entity or any parent thereof
                        outstanding immediately after such merger, consolidation
                        or business combination (either by remaining outstanding
                        or by being converted into or exchanged for voting
                        securities of the surviving entity or parent thereof);

                        (iv) there is consummated an agreement for the sale,
                        lease or other disposition by the Company of all or
                        substantially all of the Company's assets, other than a
                        sale, lease or other disposition by the Company of all
                        or substantially all of the Company's assets to an
                        entity, at least a majority of the combined voting power
                        of the outstanding securities of which are owned by
                        stockholders of the Company in substantially the same
                        proportions as their ownership of the Company
                        immediately prior to such sale; or

                        (v) there has been an entry by a court of competent
                        jurisdiction of an order confirming a plan of
                        reorganization of the Company under Chapter 11 of the
                        Bankruptcy Code.

                        Notwithstanding the foregoing, a "Change in Control"
                        shall not be deemed to have occurred by virtue of the
                        consummation of any transaction or series of integrated
                        transactions immediately following which the record
                        holders of the common stock of the Company immediately
                        prior to such transaction or series of transactions
                        continue to have substantially the same proportionate
                        ownership in an entity which owns all or substantially
                        all of the assets of the Company immediately following
                        such transaction or series of transactions.

                        For purposes of this Section 1(b), (y) "Person" shall
                        mean any person or entity other than (I) any employee
                        plan established by the Company, (II) the Company or any
                        of its affiliates (as defined in Rule 12b-2 promulgated
                        under the Securities Exchange Act of 1934, as amended
                        (the "Exchange Act")), (III) an underwriter temporarily
                        holding securities pursuant to an offering of such
                        securities, or (IV) a corporation owned, directly or
                        indirectly, by stockholders of the Company in
                        substantially the same proportions as their ownership of
                        the Company and (z) "Beneficial Owner" shall have the
                        meaning set forth in Rule 12d-3 under the Exchange Act."

        2.      Section 1(f)(v) is hereby deleted in its entirety and replaced
                with the following:

                        "(v) the termination of employment of either William L.
                        Collins, III or Steven D. Jacoby (I) by the Company
                        without "Cause," or (II) by Collins



                                       -2-
<PAGE>   3

                        or Jacoby for "Good Reason" as that term is defined and
                        applied in their respective change of control
                        agreements.

        3.      Section 3(a) is hereby deleted in its entirety and replaced with
                the following:

                "(a)    ENTITLEMENT TO BENEFITS. If a Change of Control of the
                        Company occurs, the Executive shall be entitled to the
                        benefits provided in Section 4 hereof upon his
                        termination of employment with the Company within two
                        years after the date of the Change of Control, unless
                        such termination is (i) by the Company for Cause, or
                        (ii) by the Executive other than for Good Reason. A
                        termination of the Executive's employment that entitles
                        the Executive to the payment of benefits under Section 4
                        hereof shall be referred to hereinafter as a
                        "Termination." "

        4.      The introductory paragraph of Section 4 is hereby amended by
                deleting the phrase "three-year period" and substituting in its
                place "two-year period".

        5.      Section 4(b) is hereby amended by deleting the phrase "three
                (3)" and substituting in its place "two (2)".

         The Change of Control Agreement, except as amended and modified above,
remains in full force and effect and shall be otherwise unaffected hereby.

                                         METROCALL, INC.



Date:                                By: /s/Francis A. Martin, III
     -------------------                 ------------------------------------
                                         Francis A. Martin, III
                                         Chairman of the Compensation Committee


Date:                                By: /s/Vincent D. Kelly
    --------------------                 ------------------------------------
                                          Vincent D. Kelly

                                      -3-