<PAGE>

                                                                    10.(i)(G)(6)


                                   WAIVER TO
                   POST-PETITION LOAN AND GUARANTY AGREEMENT

          WAIVER TO POST-PETITION LOAN AND GUARANTY AGREEMENT, dated as of June
26, 1998 (this "Waiver"), among MONTGOMERY WARD & CO., INCORPORATED, an Illinois
corporation and a debtor and debtor in possession ("Borrower Representative"),
MONTGOMERY WARD HOLDING CORP., a Delaware corporation and a debtor and debtor in
possession ("Parent" or "Guarantor"), as Guarantor, the other Guarantors
signatory hereto (together with Parent and the Borrower Representative, the
"Credit Parties"), GENERAL ELECTRIC CAPITAL CORPORATION, a New York corporation
(in its individual capacity, "GE Capital"), for itself, as Lender, and as Agent
(the "Agent") for Lenders, and the other Lenders signatory hereto.


                                   RECITALS
                                   --------

          WHEREAS, the Borrower Representative, the Guarantors, the Lenders and
the Agent are parties to that certain Post-Petition Loan and Guaranty Agreement,
dated as of July 8, 1997 (as amended by the Waiver and First Amendment to Post-
Petition Loan and Guaranty Agreement dated as of July 30, 1997, the Waiver and
Second Amendment to Post-Petition Loan and Guaranty Agreement dated as of
February 20, 1998, and as further amended, supplemented or modified, the "Loan
Agreement"). The Borrower Representative and the Guarantors have requested that
the Lenders agree to waive, for the limited purposes set forth herein, certain
provisions of the Loan Agreement. The Borrower Representative, the Guarantors,
the Lenders and the Agent have agreed, upon the terms and conditions specified
herein, to waive such provisions as hereinafter set forth.

          NOW, THEREFORE, in consideration of the premises and the mutual
covenants hereinafter contained and for other good and valuable consideration,
the receipt and sufficiency of which are acknowledged, the parties hereto agree
as follows:

          SECTION 1.  Defined Terms and Interpretation.

          (a)  The capitalized terms used herein which are defined in the Loan
Agreement, shall have the respective meanings assigned to them in the Loan
Agreement except as otherwise provided herein or unless the context otherwise
requires.

          (b)  Section headings in this Waiver are included herein for
convenience of reference only and shall not constitute a part of this Waiver for
any other purpose.

          (c)  No provision in this Waiver shall be interpreted or construed
against any Person because that Person or its legal representative drafted such
provision.


<PAGE>
 
          SECTION 2.  Waiver.  As of the effective date of this Waiver, Lenders
hereby waive the provisions of Section 6.3 and 8.1(r) of the Loan Agreement, for
the limited purpose of permitting the Borrower Representative to enter into an
insurance premium financing arrangement with AFCO Credit Corporation or such
other insurance premium finance company that the Debtors select pursuant to that
certain order approving the Motion of Debtors and Debtors in Possession for an
Order, Pursuant to Section 364(c)(2) of the Bankruptcy Code, Authorizing Entry
Into Insurance Premium Financing Agreement, dated May 7, 1998.

          SECTION 3.  Representations and Warranties True; No Default or Event
of Default. The Credit Parties represent and warrant to the Agent and the
Lenders that on the date of and after giving effect to the execution and
delivery of this Waiver (a) the representations and warranties set forth in the
Loan Agreement are true and correct in all material respects on the date hereof
as though made on and as of such date (unless any such representation or
warranty expressly relates to an earlier date); and (b) neither any Default nor
Event of Default has occurred and is continuing as of the date hereof.

          SECTION 4.  Reference to this Waiver and Effect on Loan Documents.

          (a)  From and after the date hereof, each reference in the Loan
Agreement (including in any Exhibit thereto) to "this Agreement," "hereunder,"
"herein" or words of like import shall mean and be a reference to the Loan
Agreement, as affected hereby.

          (b)  From and after the date of this Waiver, each reference in the
Loan Documents to the Loan Agreement shall mean and be a reference to the Loan
Agreement, as affected hereby.

          (c)  The Loan Agreement, the Notes and the other Loan Documents, as
affected hereby, shall remain in full force and effect and the Loan Documents
are hereby ratified and confirmed in all respects.

          (d)  The effectiveness of the waiver evidenced by Section 2 hereof,
shall not, except as expressly provided herein, operate as a waiver of any
right, power or remedy of the Lenders or the Agent under the Loan Agreement, or
constitute a waiver of any other provision of the Loan Agreement or any other
Loan Document.

          SECTION 5.  Effectiveness.  This Waiver shall become effective upon
receipt by the Agent of executed counterparts of this Waiver from the requisite
number of Lenders that comprise the Requisite Lenders.


                                       2

<PAGE>
 
          SECTION 6.  Governing Law; Binding Effect.  In all respects, including
all matters of construction, validity and performance, this Waiver shall be
governed by, and construed and enforced in accordance with, the internal laws of
the State of New York (without regard to conflict of law provisions) and any
applicable laws of the United States of America, and shall be binding upon the
parties hereto and their respective successors and permitted assigns.

          SECTION 7.  Execution in Counterparts.  This Waiver 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 one and the same agreement.

          SECTION 8.  Consent of Guarantors.  By their execution and delivery of
this Waiver, each Guarantor hereby consents to all of the terms and provisions
of this Waiver and ratifies and confirms that each of the Loan Documents to
which it is a party remains in full force and effect and enforceable in
accordance with their respective terms.

     IN WITNESS WHEREOF, this Waiver has been duly executed as of the date first
written above.



                    BORROWER:
 
                    MONTGOMERY WARD & CO., INCORPORATED
 


                    By:     /s/ Thomas J. Paup
                            --------------------------------------------
                    Name:   Thomas J. Paup
                            Title:  Executive Vice President and Chief
                            Financial Officer


 
                    GUARANTORS:

                    LECHMERE, INC.
 


                    By:     /s/ Don Civgin
                            --------------------------------------------
                    Name:   Don Civgin
                    Title:  Vice President and Treasurer

                                       3
<PAGE>
 
                    AMERICAN DELIVERY SERVICE COMPANY
 

                    By:     /s/ Philip D. Delk
                            --------------------------------------------
                    Name:   Philip D. Delk
                    Title:  Vice President, Secretary and Assistant
                            Treasurer


                    CONTINENTAL TRANSPORTATION, INC.
 

                    By:     /s/ Philip D. Delk
                            --------------------------------------------
                    Name:   Philip D. Delk
                    Title:  Vice President, Secretary and Assistant
                            Treasurer


                    JRI DISTRIBUTING, INC.
                    STANDARD T CHEMICAL COMPANY, INC.
                    WFL REALTY, INC.
 

                    By:     /s/ Philip D. Delk
                            --------------------------------------------
                    Name:   Philip D. Delk
                    Title:  Vice President and Secretary


                    M-W PRESTRESS, INC.
                    MW DIRECT GENERAL, INC.
                    MW DIRECT LIMITED, INC.
 

                    By:     /s/ Philip D. Delk
                            --------------------------------------------
                            Name:   Philip D. Delk
                            Title:  Secretary


                    MONTGOMERY WARD
                      INTERNATIONAL, INC.
                    MPI, INC.


                    By:     /s/ Philip D. Delk
                            --------------------------------------------
                    Name:   Philip D. Delk
                    Title:  Assistant Secretary

                                       4
<PAGE>

                    BARRETWARD PROPERTIES CO., INC.
                    BRANDYWINE DC, INC.
                    BRANDYWINE PROPERTIES, INC.
                    BRETTWARD PROPERTIES CO., INC.
                    FIRST MONT CORPORATION
                    FOURTH WYCOMBE PROPERTIES, INC.
                    GABEWARD PROPERTIES CORPORATION
                    GARDEN GROVE DEVELOPMENT CORPORATION
                    HUGA REALTY INC.
                    JOSHWARD PROPERTIES CORPORATION
                    LECHMERE DEVELOPMENT CORPORATION
                    M-W FAIRFAX PROPERTIES, INC.
                    M-W PROPERTIES CORPORATION
                    M-W RESTAURANTS REALTY CORPORATION
                    MARCOR HOUSING SYSTEMS, INC.
                    MARYWARD PROPERTIES CORPORATION
                    MF NEVADA INVESTMENTS, INC.
                    MICHAELWARD PROPERTIES CO., INC.
                    MONTGOMERY WARD DEVELOPMENT CORPORATION
                    MONTGOMERY WARD LAND CORPORATION
                    MONTGOMERY WARD PROPERTIES CORPORATION
                    MONTGOMERY WARD REALTY CORPORATION
                    MW LAND CORPORATION
                    NATIONAL HOMEFINDING SERVICE, INC.
                    998 MONROE CORPORATION
                    PAULWARD PROPERTIES CO., INC.
                    ROBERTWARD PROPERTIES CORPORATION
                    SACWARD PROPERTIES, INC.
                    SECOND MONT CORPORATION
                    7TH & CARROLL CORPORATION
                    SEVENTH MONT CORPORATION
                    618 CORPORATION
                    619 CORPORATION
                    THE 535 CORPORATION
                    THIRD WYCOMBE PROPERTIES, INC.
                    2825 DEVELOPMENT CORPORATION
                    2825 REALTY CORPORATION
                    UNIVERSITY AVENUE MARKETPLACE, INC.
                    WFL DEVELOPMENT CORPORATION
                    WYCOMBE PROPERTIES, INC.



                    By:     /s/ G. Tad Morgan
                            ----------------------------------
                    Name:   G. Tad Morgan
                    Title:  Vice President and Secretary

                                       5
<PAGE>

                    GOODE FURNITURE COMPANIES, INC.
                    MONTGOMERY WARD SECURITIES, INC.
                    R M P DEVELOPMENT CORPORATION


                    By:    /s/ G. Tad Morgan
                           --------------------------------------------
                    Name:  G. Tad Morgan
                    Title: Secretary


                    MONTGOMERY WARD HOLDING CORP.


                    By:    /s/ G. Tad Morgan
                           --------------------------------------------
                    Name:  G. Tad Morgan
                    Title: Assistant Secretary
                          
                          
                    JEFFERSON STORES, INC.

 
                    By:    /s/ G. Tad Morgan
                           --------------------------------------------
                    Name:  G. Tad Morgan
                    Title: Vice President and Treasurer


                    AGENT and as LENDER:

                    GENERAL ELECTRIC CAPITAL CORPORATION


                    By:    /s/ Paul M. Feehan
                           --------------------------------------------
                    Name:  Paul M. Feehan
                    Title: Its Authorized Signatory


                    LENDERS:

                    THE CHASE MANHATTAN BANK


                    By:    /s/ William P. Rindfuss
                           --------------------------------------------
                    Name:  William P. Rindfuss
                    Title: Vice President
 
                                        6
 
<PAGE>
 
                    BANK OF SCOTLAND


                    By:    /s/ Annie Chin Tat
                           --------------------------------------------
                    Name:  Annie Chin Tat
                    Title: Senior Vice President
                           
                           
                    BANKAMERICA BUSINESS CREDIT, INC.
                           
                           
                    By:    /s/ Roger P. Tauchman
                           --------------------------------------------
                    Name:  Roger P. Tauchman
                    Title: Vice President
                           
                           
                    BANKBOSTON RETAIL FINANCE INC.
                    (f/k/a GBFC, INC.)
                           
                           
                    By:    /s/ Mary E. Abbott
                           --------------------------------------------
                    Name:  Mary E. Abbott
                    Title: Assistant Vice President
                           
                           
                    PARIBAS
                           
                           
                    By:    /s/ John J. McCormick, III
                           --------------------------------------------
                    Name:  John J. McCormick, III
                    Title: Vice President
                           
                    By:    /s/ Edward Irwin
                           --------------------------------------------
                    Name:  Edward Irwin
                    Title: Director

                                       7
<PAGE>

                    CREDIT AGRICOLE INDOSUEZ                             
                                                                         
                                                                         
                    By:    /s/ David Bouhl                               
                           --------------------------------------------  
                    Name:  David Bouhl, F.V.P.                           
                    Title: Head of Corporate Banking, Chicago            
                                                                         
                    By:    /s/ Katherine L. Abbott                       
                           --------------------------------------------  
                    Name:  Katherine L. Abbott                           
                    Title: First Vice President                          
                                                                         
                                                                         
                    THE CIT GROUP/BUSINESS CREDIT, INC.                  
                                                                         
                                                                         
                    By:    /s/ Nicole Cangelosi                          
                           --------------------------------------------  
                    Name:  Nicole Cangelosi                              
                    Title: Assistant Secretary                           
                                                                         
                                                                         
                    CITICORP USA, INC.                                   
                                                                         
                                                                         
                    By:    /s/ Claudia Slacik                            
                           --------------------------------------------  
                    Name:  Claudia Slacik                                
                    Title: Vice President                                
                                                                         
                                                                         
                    FLEET CAPITAL CORPORATION                            
                                                                         
                                                                         
                    By:    /s/ Thomas E. Joyce                           
                           --------------------------------------------  
                    Name:  Thomas E. Joyce                               
                    Title: Senior Vice President                         
                                                                         
                                                                         
                    FLEET NATIONAL BANK                                  
                                                                         
                                                                         
                    By:    /s/ Kevin J. Chamberlain                      
                           --------------------------------------------  
                    Name:  Kevin J. Chamberlain                          
                    Title: Vice President                               
  
                                       8
<PAGE>
 
                    GOLDMAN SACHS CREDIT PARTNERS L.P.
                    

                    By:
                           --------------------------------------------
                    Name:
                    Title:


                    GREEN TREE FINANCIAL SERVICING CORPORATION


                    By:
                           --------------------------------------------
                    Name:
                    Title:


                    HELLER FINANCIAL, INC.


                    By:    /s/ Albert J. Forzano
                           --------------------------------------------
                    Name:  Albert J. Forzano
                    Title: Vice President


                    IBJ SCHRODER BUSINESS CREDIT CORP.


                    By:
                           --------------------------------------------
                    Name:
                    Title:


                    JACKSON NATIONAL LIFE INSURANCE COMPANY
                     By:  PPM FINANCE, INC.
                      Its Attorney-in-fact


                    By:    /s/ Jeffrey J. Podwika
                           --------------------------------------------
                    Name:  Jeffrey J. Podwika
                    Title: Vice President
                                 
                                                    9
             
<PAGE>
 
                    LEHMAN COMMERCIAL PAPER, INC.


                    By:
                           --------------------------------------------
                    Name:
                    Title:


                    NATIONAL CITY COMMERCIAL FINANCE, INC.


                    By:
                           --------------------------------------------
                    Name:
                    Title:


                    STAR BANK, N.A.


                    By:    /s/ Mike Ehlert
                           --------------------------------------------
                    Name:  Mike Ehlert
                    Title: Vice President

                                      10