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Exhibit 10.50(a)

EXECUTION COPY

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NEXTEL PARTNERS, INC.
as Issuer,
11% SENIOR NOTES DUE 2010

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FIRST SUPPLEMENTAL INDENTURE
Dated as of May 19, 2004

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THE BANK OF NEW YORK,
as Trustee

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        FIRST SUPPLEMENTAL INDENTURE dated as of May 19, 2004 (the "Supplemental
Indenture"), between NEXTEL PARTNERS, INC., a Delaware corporation (the
"Issuer") and THE BANK OF NEW YORK, as trustee (the "Trustee"), to the
indenture, dated as of March 10, 2000 between the Issuer and the Trustee (the
"Indenture").

W I T N E S S E T H:

        WHEREAS, the Issuer and the Trustee have heretofore executed and
delivered the Indenture providing for the issuance of 11% Senior Notes due 2010
(the "Notes") of the Issuer;

        WHEREAS, there is currently outstanding under the Indenture
$172,450,000.00 in aggregate principal amount of the Notes;

        WHEREAS, Section 9.02 of the Indenture provides that the Issuer and the
Trustee may, with the written consent of the holders of at least a majority in
aggregate principal amount at stated maturity of the outstanding Notes (the
"Requisite Consents"), enter into a supplemental indenture for the purpose of
amending the Indenture;

        WHEREAS, the Issuer has offered to purchase (the "Offer") all of the
outstanding Notes upon the terms and subject to the conditions set forth in the
Offer to Purchase and Solicitation of Consents to Proposed Amendments to Related
Indenture, dated April 28, 2004 (the "Offer to Purchase"), and the accompanying
Letter of Transmittal and Consent, as the same may be further amended,
supplemented or modified;

        WHEREAS, the Offer is conditioned upon, among other things, the proposed
amendments (the "Proposed Amendments") to the Indenture set forth herein and a
supplemental indenture in respect of the Proposed Amendments having been
executed and delivered, with the operativeness of such Proposed Amendments with
respect to the Notes being subject to, among other things, the acceptance by the
Issuer of the Notes comprising at least the Requisite Consents tendered pursuant
to the Offer and the occurrence of the Final Settlement Date (as defined in the
Offer to Purchase);

        WHEREAS, the Issuer has received and delivered to the Trustee the
Requisite Consents to effect the Proposed Amendments under the Indenture;

        WHEREAS, the Issuer has been authorized by a resolution adopted by its
Board of Directors to enter into this Supplemental Indenture;

        WHEREAS, all other acts and proceedings required by law, the Indenture
and the restated certificate of incorporation, by-laws and amended and restated
shareholders' agreement of the Issuer to execute and deliver this Supplemental
Indenture, in accordance with its terms, have been duly done and performed;

        NOW, THEREFORE, in consideration of the premises and the covenants and
agreements contained herein, and for other good and valuable consideration the
receipt of which is hereby acknowledged, and for the equal and proportionate
benefit of the holders of the Notes, the Issuer and the Trustee hereby agree as
follows:

        Section 1.    Deletion of Certain Provisions    

        Pursuant to the terms of the Offer to Purchase and the receipt of the
Requisite Consents, the Indenture is hereby amended to delete the following
sections in their entirety and, in the case of each such section, insert in lieu
thereof the phrase ["Intentionally Omitted"], and any and all references to such
sections, any and all obligations thereunder and any Event of Default under the
Indenture related solely to the following sections are hereby deleted throughout
the Indenture, and such sections and references shall be of no further force or
effect:

•Section 10.08 (Limitation on Consolidated Debt);

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•Section 10.09 (Limitation on Restricted Payments);

•Section 10.10 (Restricted Subsidiaries);

•Section 10.11 (Transactions with Affiliates);

•Section 10.12 (Liens);

•Section 10.14 (Dividend and Other Payment Restrictions Affecting Subsidiaries);

•Section 10.16 (Provision of Financial Information);

•Section 10.17 (Statement by Officers as to Default; Compliance Certificates);

•Section 10.19 (Limitations on Issuances and Sales of Equity Interests in Wholly
Owned Subsidiaries); and

•Section 10.21 (Asset Sales).

        Section 2.    Other Amendments to the Indenture    

        All definitions in the Indenture which are used exclusively in the
sections and clauses deleted pursuant to Section 1 of this Supplemental
Indenture are hereby deleted.

        Section 3.    Effectiveness; Operativeness    

        (a)   Subject to Section 3(c) below, this Supplemental Indenture will
become binding on the parties hereto upon the delivery by the Issuer of (i) an
Officers' Certificate (as defined in the Indenture) to the effect that the
Issuer has accepted for purchase at least a majority in aggregate principal
amount of the outstanding Notes, and (ii) an Opinion of Counsel (as defined in
the Indenture) required by Section 9.03 of the Indenture and in the form
attached hereto as Exhibit A (subject to customary limitations, assumptions and
qualifications).

        (b)   Subject to Section 3(c) below, this Supplemental Indenture will
become effective and operative on and simultaneously with the Final Settlement
Date.

        (c)   Notwithstanding the foregoing, this Supplemental Indenture will
cease to be binding, effective or operative if the Issuer does not purchase in
the Offer outstanding Notes comprising at least the Requisite Consents prior to
the termination of the Offer.

        Section 4.    Reference to and Effect on the Indenture    

        (a)   On and after the effective date of this Supplemental Indenture,
each reference in the Indenture to "this Indenture," "hereunder," "hereof," or
"herein" shall mean and be a reference to the Indenture as supplemented by this
Supplemental Indenture unless the context otherwise requires.

        (b)   Except as specifically amended above, the Indenture shall remain
in full force and effect and is hereby ratified and confirmed.

        Section 5.    Governing Law    

        This Supplemental Indenture shall be construed and enforced in
accordance with the laws of the State of New York, including without limitation
Section 5-1401 of the New York General Obligation Law.

        Section 6.    Defined Terms    

        Unless otherwise indicated, capitalized terms used herein and not
defined shall have the respective meanings given such terms in the Indenture.

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        Section 7.    Trust Indenture Act Controls    

        If any provision of this Supplemental Indenture limits, qualifies or
conflicts with another provision of this Supplemental Indenture or the Indenture
that is required to be included by the Trust Indenture Act of 1939, as amended
(the "Act"), as in force at the date this Supplemental Indenture is executed,
the provision required by the Act shall control.

        Section 8.    Trustee Disclaimer    

        The recitals contained in this Supplemental Indenture shall be taken as
the statements of the Issuer, and the Trustee assumes no responsibility for
their correctness. The Trustee makes no representations as to the validity or
sufficiency of this Supplemental Indenture.

        Section 9.    Counterparts and Method of Execution    

        This Supplemental Indenture may be executed in several counterparts, all
of which together shall constitute one agreement binding on all parties hereto,
notwithstanding that all the parties have not signed the same counterpart.

        Section 10.    Titles    

        Section titles are for descriptive purposes only and shall not control
or alter the meaning of this Supplemental Indenture as set forth in the text.

        Section 11.    Severability    

        In case any provision of this Supplemental Indenture shall be invalid,
illegal or unenforceable, the validity, legality and enforceability of the
remaining provisions shall not in any way be effected or impaired thereby.

[Signature pages to follow]

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        IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be executed as of the day and year first above written.

    NEXTEL PARTNERS, INC.
 
 
By:
       

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Name:
Title:
 
 
THE BANK OF NEW YORK

 
 
By:
       

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Name:
Title:

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EXHIBIT A

Opinion of Counsel

        The execution of the Supplemental Indenture is permitted by the
Indenture.

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Exhibit 10.50(a)

EXHIBIT A Opinion of Counsel