Exhibit  10.6


 


LETTER AMENDMENT NO. 4


TO


THIRD AMENDED AND RESTATED MASTER SHELF AGREEMENT


 


As of November 22, 2005


 


The Prudential Insurance Company of America 


Pruco Life Insurance Company 


Prudential Investment Management, Inc. (“Prudential”)


Pruco Life Insurance Company of New Jersey


Gibraltar Life Insurance Co., Ltd.


RGA Reinsurance Company


American Bankers Life Assurance Company of Florida, Inc.


Fortis Benefits Insurance Company


Connecticut General Life Insurance Company


c/o Prudential Capital Group


2200 Ross Avenue, Suite 4200E 


Dallas, Texas 75201


 


Ladies and Gentlemen:


 


We refer to the Third Amended and Restated Master
Shelf Agreement dated as of December 19, 1991 (effective as of January 13,
2003), as amended by Letter Amendment No. 1 to Third Amended and Restated
Master Shelf Agreement dated as of April 24, 2003, Letter Amendment No. 2
to Third Amended and Restated Master Shelf Agreement dated as of June 29,
2004 and Letter Amendment No. 3 to Third Amended and Restated Master Shelf
Agreement dated as of December 15, 2004 (as amended, the “Agreement”), among Prudential, the Purchasers party thereto
and Western Gas Resources, Inc., a Delaware corporation (the “Company”).  Unless
otherwise defined in this Letter Amendment No. 4 to Third Amended and Restated
Master Shelf Agreement (this “Amendment”),
the terms defined in the Agreement shall be used herein as therein defined.


 


The Company has requested and, subject to the terms
and conditions specified herein, the undersigned holders of the Notes are willing
to make, certain amendments to the Agreement and the Company Pledge Agreement,
all as more particularly set forth herein.


 


1.                                      Amendments
to the Agreement.  Subject to the
accuracy of the representations and warranties set forth in paragraph 3 hereof
and satisfaction of the conditions set forth in paragraph 4(c) hereof, the
undersigned holders of the Notes hereby agree with the Company to amend,
effective as of the date first above written, the Agreement as follows:


 


(a)                                  Paragraph 5P.  Covenant to Pledge
Stock.  Paragraph 5P of the
Agreement is amended by deleting it its entirety and inserting the following in
lieu thereof:


 





















 


“5P. Covenant to Pledge Stock.
The Company shall, and shall cause its Subsidiaries to (i) promptly (and
in any event within 30 days after acquiring such equity interests) pledge to
the Collateral Agent (as security for the Notes and the Guaranties) (A) the
equity interests in each Domestic Subsidiary Guarantor that is now owned or
hereafter acquired by it and (B) any other equity interests that are
pledged to NCNB, as agent for the lenders under the NCNB Agreement (including,
without limitation, the pledge of 65% of the equity interests in Western Gas
Resources Canada Company pursuant to the Power Pledge Agreement), in each case
pursuant to such documents as the Collateral Agent shall deem appropriate for
such purpose and (ii) concurrently with each such pledge, deliver to the
Collateral Agent documents of the types referred to in clauses (ii) through
(vii) of paragraph 3A(1) and favorable opinions of counsel to such
Person (which shall cover, among other things, the legality, validity, binding
effect and enforceability of the documentation referred to in clause (i) above),
all in form, content and scope reasonably satisfactory to the Collateral Agent;
provided, that, no PUC Subsidiary shall be required to execute and
deliver any Security Document pursuant to this paragraph 5P or to approve an
increase in the underlying amount secured by such Security Document unless all
required regulatory approvals shall have been obtained for such Security
Document from each applicable PUC and, to the extent applicable, FERC.  The Company shall cause each PUC Subsidiary
required to deliver a Security Document or approve an increase in the
underlying amount pursuant to paragraph 5P to use its best efforts to obtain
the approval of the applicable PUC and, to the extent applicable, FERC for such
Security Document (or increase in the amount underlying and secured by such
Security Document).  In the event that
the any PUC or FERC shall require that the equity interests of a PUC Subsidiary
be released from the Lien in favor of the Collateral Agent or shall not approve
the PUC Subsidiary to secure an increased amount by such Lien or Security
Document, the Collateral Agent shall so release such equity interests or limit
the amount secured to the previously approved amount, if applicable; provided
that all equity interests of a replacement Subsidiary acceptable to Prudential
shall have been pledged to Collateral Agent for the benefit of the holders of
the Notes unless all potential replacement Subsidiaries are PUC Subsidiaries
and are prohibited by the applicable PUCs or FERC from having their equity
interests pledged to the Collateral Agent.”


 


(b)                                 Paragraph 10(B). 
Definitions.  


 


(I)                                    Paragraph
10B of the Agreement is amended by deleting “MGTC,” from the existing
definition of “Guarantor”. 


 


(II)                                Paragraph
10B of the Agreement is further amended by deleting the definition of “MIGC
Pledge Agreement”.


 


(III)                            Paragraph
10B of the Agreement is further amended by deleting the existing definitions of
“Intercreditor Agreement”, “NCNB Agreement” and “Pledge Agreement” and
inserting the following definitions in lieu thereof:


 


“Intercreditor
Agreement” shall mean that certain Amended and Restated
Intercreditor Agreement dated as of November 22, 2005, among


 


2





















 


Prudential, the holders of the Notes, the banks party
to the NCNB Agreement, and Bank of America, N.A., as collateral agent, as the
same may be amended, restated, supplemented or otherwise modified from time to
time in compliance with the terms hereof.


 


“NCNB
Agreement” shall mean that certain Amended and Restated Credit
Agreement dated as of November 22, 2005, among the Company, Bank of
America, N.A., as Administrative Agent and L/C Issuer, BNP Paribas, JPMorgan
Chase Bank, The Royal Bank of Scotland plc, Wachovia Bank, National Association
and Wells Fargo Bank, N.A., as Co-Syndication Agents, Fortis Capital Corp. and Union
Bank of California, N.A., as Co-Documentation Agents, and the lenders party
thereto, as the provisions thereof may from time to time be amended or waived
in compliance with paragraph 6E.


 


“Pledge
Agreement” shall mean, collectively, the Company Pledge Agreement,
the Power Pledge Agreement and each other pledge agreement delivered from time
to time by a Subsidiary to the holders of the Notes pursuant to paragraph 5N or
paragraph 5P, in each case as the provisions thereof may be from time to time
amended or waived in compliance with the terms thereof. 


 


(IV)                            The
following definition is inserted in paragraph 10B in the appropriate
alphabetical order:


 


“Power Pledge
Agreement” shall mean that certain Foreign Subsidiary Pledge
Agreement, dated as of November 22, 2005, by Western Power Services, Inc.
in favor of the Collateral Agent, as the provisions thereof may be from time to
time amended or waived in compliance with the terms thereof.


 


2.                                      Amendments
to the Company Pledge Agreement.  Subject
to the accuracy of the representations and warranties set forth in paragraph 3
hereof and satisfaction of the conditions set forth in paragraph 4(c) hereof,
the undersigned holders of the Notes hereby agree with the Company to amend,
effective as of the date first above written, the Company Pledge Agreement by
deleting the existing definition of Intercreditor Agreement contained therein
and inserting the following in lieu thereof:


 


 
“Intercreditor Agreement”
shall mean that certain Amended and Restated Intercreditor Agreement dated as
of November 22, 2005, among Prudential, the holders of the Notes, the
banks party to the NCNB Agreement, and Bank of America, N.A., as collateral
agent, as the same may be amended, restated, supplemented or otherwise modified
from time to time.


 


3.                                      Representations
and Warranties.  In order to induce
each of you to enter into this Amendment, the Company hereby represents and
warrants as follows:


 


(a)                                  Due Authorization; Noncontravention.  The execution, delivery and performance by
the Company and each Guarantor of this Amendment, the Agreement as


 


3





















 


amended hereby, the
Notes, the Guaranties, the Intercreditor Agreement and the Security Documents
have in each case been duly authorized by all necessary corporate or limited
liability company action, as applicable, and do not and will not (i) contravene
the terms of the charter and by-laws or other organizational documents of the
Company, any Guarantor, Western Power Services, Inc. or Western Gas Resources Canada Company, (ii) conflict
with or result in any breach or contravention of, or the creation of any Lien
(other than the Liens created by the Security Documents) under, any document
evidencing any contractual obligation to which any such Person is a party or
any order, injunction, writ or decree of any governmental authority binding on
any such Person or its property, or (iii) violate any applicable law
binding on or affecting any such Person.


 


(b)                                 Binding Effect.  This
Amendment, the Agreement as amended hereby, the Notes, the Guaranties, the
Intercreditor Agreement and the Security Documents constitute the legal, valid
and binding obligations of the Company, the Guarantors and Western Power
Services, Inc., enforceable against such Persons in accordance with their
respective terms, except as enforceability may be limited by applicable
bankruptcy, insolvency, or similar laws affecting the enforcement of creditors’
rights generally or by equitable principles of general applicability.


 


(c)                                  Representations and Warranties.  The representations and warranties of the
Company, the Guarantors and Western Power Services, Inc. set forth in the
Agreement, the Guaranties and the Security Documents are true and correct on
and as of the date hereof, both before and after giving effect to the
effectiveness of this Amendment (except to the extent such representations and
warranties expressly are limited to an earlier date, in which such
representations and warranties are true and correct on and as of such earlier
date).


 


(d)                                 No Defaults.  No
Default or Event of Default exists under the Agreement, the Notes, any
Guaranty, any Security Document or any other agreement or instrument executed
in connection therewith and no default or event of default exists under the
NCNB Agreement, any agreement or instrument executed in connection therewith or
any other material contract or agreement to which the Company or any of the
Guarantors is a party, and, to the Company’s knowledge, no such default or
event of default is imminent. 


 


4.                                      Miscellaneous.


 


(a)                                  Effect
on Agreement.  On and after the
effective date of this Amendment, each reference in the Agreement to “this
Agreement”, “hereunder”, “hereof”, or words of like import referring to the
Agreement and each reference in the Notes and all other documents executed in
connection with the Agreement to “the Agreement”, “thereunder”, “thereof”, or
words of like import referring to the Agreement shall mean the Agreement as
amended by this Amendment.  The
Agreement, as amended by this Amendment, is and shall continue to be in full
force and effect and is hereby in all respects ratified and confirmed. 


 


(b)                                 Counterparts.  This Amendment may be executed in any number
of counterparts and by any combination of the parties hereto in separate counterparts,
each of which counterparts shall be an original and all of which taken together
shall constitute one and the same Amendment. 
Delivery of this Amendment may be made by telecopy or electronic
transmission of a duly executed counterpart copy hereof; provided that
any such delivery by electronic


 


4





















 


transmission shall be effective only if transmitted in .pdf format,
..tif format or other format in which the text is not readily modifiable by any
recipient thereof.


 


(c)                                  Effectiveness.  This Amendment shall become effective as of
the date first above written when and if each of the conditions set forth in
this subparagraph (c) shall have been satisfied.


 


(I)                                    Amendment.  Counterparts of this Amendment shall have
been executed by the Company, each Guarantor and the Required Holder(s) and
shall have been delivered to Prudential.


 


(II)                                NCNB
Loan Documents.  The Amended and
Restated Credit Agreement dated as of November 22, 2005, among the
Company, Bank of America, N.A., and the other lenders party thereto and the
Loan Documents (as defined therein) shall have been executed by all parties
thereto, a final copy and execution pages thereof shall have been
delivered to Prudential and all of such Loan Documents shall be in form and
substance satisfactory to Prudential and in full force and effect.


 


(III)                            Intercreditor
Agreement.  The Intercreditor
Agreement shall have been executed by all parties thereto, a counterpart
thereof shall have been delivered to Prudential and such Intercreditor
Agreement shall be in form and substance satisfactory to Prudential and in full
force and effect. 


 


(IV)                            Power
Pledge Agreement.  The Power Pledge
Agreement shall have been executed by Western Power Services, Inc., a
counterpart thereof shall have been delivered to Prudential and such Power
Pledge Agreement shall be in form and substance satisfactory to Prudential and
in full force and effect.


 


(V)                                Western
Power Services, Inc. Secretary’s Certificate, Resolutions, etc.  Prudential
shall have received from Western Power Services, Inc. documents of the types referred to in clauses
(ii) through (vii) of paragraph 3A(1) of the Agreement, and such
documents shall be in form and substance satisfactory to Prudential and in full
force and effect.


 


(VI)                            Representations
and Warranties.  Each of the
representations and warranties made in this Amendment shall be true and correct
on and as of the date hereof as if made on and as of such date, both before and
after giving effect to this Amendment.


 


(d)                                 Expenses.  The Company confirms its agreement, pursuant
to paragraph 11B of the Agreement, to pay promptly all expenses of the
undersigned holders of Notes related to the preparation, reproduction,
execution and delivery of this Amendment and all matters contemplated hereby,
including without limitation all fees and expenses of counsel to such parties. 


 


(e)                                  Governing
Law.  THIS AMENDMENT SHALL BE CONSTRUED
AND ENFORCED IN ACCORDANCE WITH, AND THE RIGHTS OF THE PARTIES SHALL BE
GOVERNED BY, THE LAW OF THE STATE OF NEW YORK.


 


5





















 


(f)                                    Release from Guaranty.  As
of the effective date of this Amendment, MGTC is hereby released from its
obligations under that certain Guaranty dated as of October 14, 1999 (the “MGTC Guaranty”);
provided, however,
that the release and termination effected hereby shall not extend to or affect
any obligations or liabilities of MGTC under provisions of the MGTC Guaranty
which by their terms are to survive termination of the MGTC Guaranty.


 


(g)                                 Release of MIGC Pledge Agreement.  As of the effective date of this Amendment,
MIGC is hereby released from its obligations under that certain Stock Pledge
Agreement made by MIGC as of April 29, 1999 (the “MIGC Pledge
Agreement”), and the MIGC Pledge Agreement is hereby terminated; provided, however, that
the release and termination effected hereby shall not extend to or affect any
obligations or liabilities of MIGC under provisions of the MIGC Pledge
Agreement which by their terms are to survive termination of the MIGC Pledge
Agreement.  


 


(h)                                 Affirmation of Obligations and Liens.  Notwithstanding that such consent is not
required thereunder, each of the Guarantors consents to the execution and
delivery of this Amendment by the parties hereto, and consents to the
transactions contemplated hereby, including, without limitation, the release
and termination of MGTC’s obligations under the MGTC Guaranty pursuant to
paragraph 4(f) hereof and the termination of the MIGC Pledge Agreement
pursuant to paragraph 4(g) hereof. 
As a material inducement to the undersigned to amend the Agreement, each
of the Guarantors respectively (i) acknowledges and confirms the
continuing existence, validity and effectiveness of the Guaranty and Pledge
Agreement, if any, to which it is a party, and any Liens granted thereunder,
and (ii) agrees that the execution, delivery and performance of this
Amendment shall not in any way release, diminish, impair, reduce or otherwise
affect its obligations under any such Guaranty or Pledge Agreement or any Liens
granted thereunder except that, upon the effectiveness of, and on and after the
date of this Amendment, each reference in such Guaranty or Pledge Agreement to
the “Shelf Agreement” shall mean the Agreement as amended by this Amendment, and
as the same may be further amended or modified from time to time. 


 


(i)                                     Headings.  The
headings of the various paragraphs and subparagraphs of this Amendment are for
convenience of reference only and shall not modify, define, expand or limit any
of the terms or provisions hereof.


 


(j)                                     FINAL AGREEMENT. THE AGREEMENT, AS AMENDED BY THIS AMENDMENT, TOGETHER
WITH THE NOTES, THE GUARANTIES AS AMENDED BY THIS AMENDMENT, THE INTERCREDITOR
AGREEMENT AND THE SECURITY DOCUMENTS, REPRESENT THE FINAL AGREEMENT BETWEEN THE
PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS,
OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. 
THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.


 


[Remainder of page is intentionally left blank; signature pages follow]


 


6





















 


If you agree to the terms and provisions hereof, please evidence your
agreement by executing and returning a counterpart of this Amendment to Western
Gas Resources, Inc., 1099 18th Street, Suite 1200, Denver, CO 80202,
Attention: General Counsel.


 


	
   

  	
  Very truly yours,

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  WESTERN GAS RESOURCES, INC.

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ William J. Krysiak

  	
   

  
	
   

  	
   

  	
  William J. Krysiak

  
	
   

  	
   

  	
  Executive Vice President- CFO

  



 


 


Agreed as of the date first above written:


 


	
  THE PRUDENTIAL INSURANCE COMPANY

  	
   

  
	
  OF
  AMERICA

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   Vice
  President

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  PRUCO LIFE INSURANCE COMPANY

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   Vice
  President

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  PRUCO LIFE INSURANCE COMPANY OF

  	
   

  
	
  NEW
  JERSEY

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   Vice
  President

  	
   

  



 


Signature Page to Amendment No. 4


 





















 


	
  GIBRALTAR LIFE INSURANCE CO., LTD.

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Investment Management (Japan),

  	
   

  
	
   

  	
  Inc., as Investment Manager

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Investment Management, Inc.,

  	
   

  
	
   

  	
  as Sub-Adviser

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   

  	
   

  	
   Vice
  President

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  RGA REINSURANCE COMPANY

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Private Placement Investors,

  	
   

  
	
   

  	
  L.P. (as Investment Advisor)

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Private Placement Investors, Inc.

  	
   

  
	
   

  	
  (as its General Partner)

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   

  	
   

  	
   Vice
  President

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  AMERICAN BANKERS LIFE ASSURANCE

  	
   

  
	
  COMPANY
  OF FLORIDA, INC.

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Private Placement Investors,

  	
   

  
	
   

  	
  L.P. (as Investment Advisor)

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Private Placement Investors, Inc.

  	
   

  
	
   

  	
  (as its General Partner)

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   

  	
   

  	
   Vice
  President

  	
   

  



 


Signature Page to Amendment No. 4


 





















 


	
  FORTIS BENEFITS INSURANCE COMPANY

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Private Placement Investors,

  	
   

  
	
   

  	
  L.P. (as Investment Advisor)

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Private Placement Investors, Inc.

  	
   

  
	
   

  	
  (as its General Partner)

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   

  	
   

  	
   Vice
  President

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
  CONNECTICUT GENERAL LIFE INSURANCE

  	
   

  
	
  COMPANY

  	
   

  
	
   

  	
   

  
	
  By:

  	
  Prudential Investment Management, Inc.,

  	
   

  
	
   

  	
  as Investment Manager

  	
   

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/

  	
   Brian E.
  Lemmons

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   Brian E.
  Lemmons

  	
   

  
	
   

  	
   

  	
   

  	
   Vice
  President

  	
   

  
									



 


Signature Page to Amendment No. 4


 





















 


	
  Agreed and acknowledged by each of the undersigned
  for

  	
   

  
	
  the purposes set forth in paragraphs 4(f),
  (g) and (h):

  	
   

  
	
   

  
	
   

  	
  MIGC, INC.

  
	
   

  	
  WESTERN GAS RESOURCES-TEXAS, INC.

  
	
   

  	
  MOUNTAIN GAS RESOURCES, INC.

  
	
   

  	
  LANCE OIL & GAS COMPANY, INC.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ William J. Krysiak

  	
   

  
	
   

  	
   

  	
  William J. Krysiak

  
	
   

  	
   

  	
  Executive Vice President- CFO

  
	
   

  	
   

  
	
   

  	
  WESTERN GAS WYOMING, L.L.C.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  Western Gas Resources, Inc., its sole member

  
	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  /s/ William J. Krysiak

  	
   

  
	
   

  	
   

  	
   

  	
  William J. Krysiak

  
	
   

  	
   

  	
   

  	
  Executive Vice President- CFO

  
								



 


Signature Page to Amendment No. 4


 





















 


	
  Agreed and acknowledged by the undersigned for

  	
   

  
	
  the purposes set forth in paragraphs 2 and 4(g):

  	
   

  
	
   

  
	
   

  	
  BANK OF AMERICA, N.A.,

  
	
   

  	
  as Collateral Agent

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Joseph F. Scott

  	
   

  
	
   

  	
  Name: Joseph F. Scott

  
	
   

  	
  Title: Vice President

  
					



 


Signature Page to Amendment No. 4