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                                                                    EXHIBIT 10.4

                       EXECUTIVE RETENTION BONUS AGREEMENT

         THIS EXECUTIVE RETENTION BONUS AGREEMENT (this "Agreement") is by and
between Allegiance Telecom Company Worldwide (the "Company") and Mark B.
Tresnowski (the "Employee"), effective as of the date set forth under the
signature of the Company below.

         WHEREAS, Employee is an employee of the Company or an Affiliate of the
Company; and WHEREAS, the Compensation Committee of Allegiance Telecom, Inc.'s
Board of Directors recognizes the uncertainty and questions that may arise in
the context of a recapitalization transaction which could result in the
departure or distraction of key employee personnel to the detriment of
Allegiance Telecom, Inc., its Affiliates and its stakeholders; and WHEREAS, the
Company has determined that it is in the best interests of the Company, its
Affiliates and its stakeholders to incentivize key employees to remain at the
Company or its Affiliates during the process of, and for a reasonable time
after, the recapitalization transaction.

         NOW, THEREFORE, in consideration for the promises and mutual covenants
herein contained, it is hereby agreed by the parties as follows:

1.   RETENTION PAYMENT. Employee will be entitled to an aggregate retention
     bonus equal to $300,000 (the "Retention Payment"), payable in installments
     set forth below, provided that Employee has been continuously employed by
     the Company or any Affiliate through December 31, 2003 and subject to the
     other terms and conditions of this Agreement:

     o   25% of the Retention Payment will be made on or about March 14, 2003;

     o   25% of the Retention Payment will be made on or about September 8,
         2003; and

     o   50% of the Retention Payment will be made on or about December 31,
         2003.

2.   TERMINATION OF EMPLOYMENT.

     (a) TERMINATION DUE TO DEATH, DISABILITY OR BY COMPANY WITHOUT CAUSE.
         Notwithstanding anything herein to the contrary, if, prior to December
         31, 2003, Employee's employment with the Company and all Affiliates is
         terminated because of (i) death of Employee, (ii) Disability of
         Employee or (iii) termination by the Company or any Affiliate without
         Cause, then Employee will be entitled to the FULL AMOUNT of the
         Retention Payment.

     (b) TERMINATION BY COMPANY FOR CAUSE OR EMPLOYEE RESIGNATION FOR ANY
         REASON. If, prior to December 31, 2003, Employee's employment with the
         Company and all Affiliates is terminated (i) by the Company or any
         Affiliate for Cause or (ii) because of Employee's resignation for any
         reason, then Employee will (A) immediately repay all Net Retention
         Payment received and (B) not have any rights to any Retention Payment.

3.   NO SPECIAL EMPLOYMENT RIGHTS. Nothing in this Agreement will (a) be deemed
     to confer on Employee any right to employment or continued employment with
     the Company or any Affiliate, or (b) affect any right that the Company or
     any Affiliate may have to terminate the employment of Employee at any time.

4.   OTHER EMPLOYEE BENEFITS. No payments made hereunder shall be includible as
     an annual or long-term bonus or other compensation in creditable
     compensation in computing benefits under any employee benefit plan of the
     Company or any Affiliate.

5.   WITHHOLDINGS. The Company may withhold from all payments due to Employee
     (or his/her beneficiary or estate) hereunder all taxes or other amounts
     which, by applicable federal, state, local or other law, the Company is
     required to withhold therefrom.

6.   OBLIGATIONS TO THE COMPANY; RIGHT TO WITHHOLD FROM PAYCHECK. If Employee
     becomes entitled to payment of any installment of a Retention Payment
     hereunder, and if at such time Employee has outstanding any debt,
     obligation, or other liability representing an amount owed to the Company
     or any Affiliate, any amount of such indebtedness, obligation or other
     liability may, at the Company's option, to the extent lawful, be deducted
     by the Company from the amount of the Net Retention Payment then payable to
     Employee or Employee's beneficiary pursuant to this Agreement. In the event
     Employee is required to repay any Net Retention Payment, Employee
     authorizes the Company and its Affiliates to deduct any amount of such
     payment from any salary, bonus, vacation pay, commissions or any other
     compensation earned by Employee and Employee specifically authorizes the

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     Company and its Affiliates to deduct any amount of such payment from
     Employee's paycheck(s), including Employee's final paycheck (to the extent
     lawful). Any such deductions shall not relieve Employee of his/her
     obligation to pay any remaining amounts owing under this Agreement or any
     other agreement. CONSENT TO SUCH DEDUCTION(S) SHALL BE EVIDENCED BY
     EMPLOYEE'S SIGNATURE ON THIS AGREEMENT.

7.   LETTER OF CREDIT. The Company shall use its reasonable efforts to support
     its obligations under this Agreement with a letter of credit in a form
     acceptable to the Company.

8.   CONFIDENTIAL INFORMATION. Employee shall keep the existence and contents of
     this Agreement in strictest confidence and shall not disclose it to anyone
     other than Employee's tax and financial advisors, attorneys and immediate
     family members, provided that Employee advises such persons that the
     information is confidential. Employee may discuss this Agreement with the
     Company's Human Resources or Legal departments or the head of Employee's
     department.

9.   DEFINITIONS. As used in this Agreement, the following terms shall have the
     respective meanings set forth below:

     (a) "Affiliate" means any entity that directly or indirectly is controlled
         by, controls or is under common control with the Company.

     (b) "Cause" means (i) embezzlement or misappropriation of funds of the
         Company, any of its Affiliates or their successors; (ii) use of illegal
         drugs or alcohol that materially impairs Employee's ability to fulfill
         his duties as an employee; (iii) willful disclosure of trade secrets or
         confidential information of or any material violation of any other
         material published policy of the Company, any of its affiliates or
         their successors; or (iv) conviction or confession of a criminal
         felony.

     (c) "Company" means Allegiance Telecom Company Worldwide, a Delaware
         corporation and the successor to, or transferee of all or substantially
         all of the assets of, the Company.

     (d) "Disability" means "disability" as defined in the Company's Long-Term
         Disability Insurance Plan.

     (e) "Net Retention Payment" means the Retention Payment less any
         withholdings taken by the Company or any Affiliate for taxes and other
         governmental charges.

10.  SUCCESSORS; BINDING AGREEMENT. (a) This Agreement is personal to Employee
     and without the prior written consent of the Company, shall not be
     assignable by Employee otherwise than by will or the laws of descent and
     distribution. This Agreement shall inure to the benefit of and be
     enforceable by Employee's legal representatives. (b) This Agreement shall
     inure to the benefit of and be binding upon the Company and its successors.
     The Company agrees that, for so long as it has any obligations under this
     Agreement, it will cause any successor or transferee (if other than the
     Company) to unconditionally assume, by written instrument delivered to
     Employee (or his/her beneficiary or estate), all of the obligations of the
     Company hereunder.

11.  NOTICES. All notices, demands or other communications to be given or
     delivered under or by reason of the provisions of this Agreement shall be
     in writing and shall be deemed to have been given when personally delivered
     or on the fifth day after being sent via U.S. certified or registered mail,
     return receipt requested:

        TO THE COMPANY:
        Allegiance Telecom Company Worldwide,
        Attn: Pati Marano, Human Resources Department
        9201 North Central Expressway
        Dallas, TX 75231
        Telephone:  (469) 259-2325

        TO EMPLOYEE: at Employee's office location or primary residence
        listed in the Company's records

     or to such other address or to the attention of such other person as the
     recipient party has specified by prior written notice to the sending party.
     Notwithstanding anything herein to the contrary, the Company may provide
     Employee with written notice by sending Employee an email.

12.  GOVERNING LAW; VALIDITY. The validity, interpretation, and enforcement of
     this Agreement shall be governed by the laws of the State of Texas as to
     all matters, including, but not limited to, matters of validity,
     construction and performance, without regard to principles of conflict of
     laws. Whenever possible, each provision of this Agreement shall be
     interpreted in such manner as to be effective and valid under applicable
     law, but if any provision of this Agreement is held to be invalid, illegal
     or unenforceable in any respect under any applicable law or rule in any

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     jurisdiction, such invalidity, illegality or unenforceability shall not
     affect any other provision or any other jurisdiction, but this Agreement
     shall be reformed, construed and enforced in such jurisdiction as if such
     invalid, illegal or unenforceable provision had never been contained
     herein.

13.  CONSENT TO JURISDICTION; AGENT FOR SERVICE OF PROCESS; LIMITATION OF
     LIABILITY. Employee consents to the non-exclusive jurisdiction and venue in
     the state and federal courts located in Dallas County, Texas and waives any
     defense of forum non conveniens. Service of legal process on the Company
     with respect to a claim under this Agreement shall be made upon the General
     Counsel of Allegiance Telecom, Inc. IN NO EVENT SHALL THE COMPANY OR ANY
     AFFILIATE BE LIABLE UNDER OR RELATING TO THIS AGREEMENT FOR ANY AMOUNT IN
     EXCESS OF THE RETENTION PAYMENT. NOTWITHSTANDING ANY OTHER PROVISION
     HEREOF, THE COMPANY SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL,
     SPECIAL, CONSEQUENTIAL, EXEMPLARY OR PUNITIVE DAMAGES.

14.  INTEREST; PAYMENT OF COLLECTION FEES. Employee agrees to repay all amounts
     due under this Agreement to the Company within ten (10) days of Employee's
     termination date. Any amounts due to the Company under this Agreement and
     not paid shall accrue interest at 1.5% per month (or if less, the maximum
     rate permissible under law) starting from the 11th day after Employee's
     termination date until paid. Employee agrees to pay all of Company's costs
     of collection relating to or in connection with this Agreement, including
     reasonable attorneys' fees.

15.  WAIVER. Employee's or the Company's failure to insist upon strict
     compliance with any provision hereof or any other provision of this
     Agreement or the failure to assert any right Employee or the Company may
     have hereunder shall not be deemed to be a waiver of such provision or
     right or any other provision or right of this Agreement.

16.  ENTIRE AGREEMENT; NO AMENDMENT. This Agreement contains the entire
     agreement and supersedes all prior and contemporaneous oral or written
     communications and agreements between the parties relating to the subject
     matter of this Agreement. Neither this Agreement, nor any of its terms, may
     be changed, added to, amended, waived or varied except in writing signed by
     Employee and by either the CEO, CFO or COO of the Company.

17.  COUNTERPARTS; DELIVERY BY FACSIMILE. This Agreement may be executed in
     counterparts, each of which shall be deemed to be an original and all of
     which together shall constitute one and the same instrument. This Agreement
     any amendments hereto to the extent signed and delivered by means of a
     facsimile machine, will be treated in all manner and respects as an
     original agreement and will be considered to have the same binding legal
     effect as if it were the original signed version thereof delivered in
     person. At the request of any party, each other party hereto will reexecute
     original forms thereof and deliver them to all other parties. No party
     hereto will raise the use of a facsimile machine to deliver a signature or
     the fact that any signature or agreement or instrument was transmitted or
     communicated through the use of a facsimile machine as a defense to the
     formation or enforceability of a contract and each such party forever
     waives any such defense.


IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the
dates set forth below.

BY SIGNING BELOW, EMPLOYEE ACKNOWLEDGES THAT HE/SHE HAS (A) READ THIS AGREEMENT;
AND (B) UNDERSTANDS THE TERMS AND CONDITIONS OF THIS AGREEMENT.


ALLEGIANCE TELECOM COMPANY WORLDWIDE
By: ______________________________________
Name: Royce J. Holland
Its: Chairman and Chief Executive Officer
Effective Date: __________________________


EMPLOYEE: ________________________________
Printed Name : ___________________________
Date: ____________________________________



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