Exhibit 2.4


                 FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT

         This FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT (this "Amendment")
is entered into as of the 6th day of April, 2006 by and among ONEOK, Inc., an
Oklahoma corporation ("ONEOK"), Northern Border Partners, L.P., a Delaware
limited partnership ("Northern Border"), and Northern Border Intermediate
Limited Partnership ("NBILP", and together with Northern Border, the "NBP
Partnerships") (each a "Party" and collectively, the "Parties"). Capitalized
terms used in this Amendment but not defined shall have the respective meanings
given to such terms in the Purchase Agreement.

                                   WITNESSETH

         WHEREAS, ONEOK and Northern Border entered into that certain Purchase
and Sale Agreement dated as of February 14, 2006 (the "Original Purchase
Agreement"), pursuant to which ONEOK agreed to sell to Northern Border all of
the issued and outstanding Equity Interests in the Companies;

         WHEREAS, the Parties entered into that certain Assignment of Purchase
Right dated April 6th, 2006, pursuant to which, among other things, Northern
Border assigned its right to purchase the Companies to NBILP, and NBILP assumed
the obligation to pay the purchase price to ONEOK (the Original Purchase
Agreement, as assigned by the Assignment of Purchase Right, is referred to as
the "Purchase Agreement"); and

         WHEREAS, the Parties desire to amend certain terms of the Purchase
Agreement.

         NOW, THEREFORE, in consideration of the premises and mutual agreements
and covenants herein contained, and intending to be legally bound hereby, the
Parties hereto agree as follows:

         1. Representations and Warranties of ONEOK. The following Section 2.23
is added to the Purchase Agreement:

            "2.23 No Transfer to ONEOK. Except in connection with Sections 6.7
            and 6.10 of this Agreement, and except as fully reflected in the
            working capital adjustment described in Section 1.4 of this
            Agreement, from the close of business on March 31, 2006 until
            Closing, no Entity has distributed, dividended or otherwise
            transferred any cash or assets to ONEOK, any other Entity or any
            other Affiliate of ONEOK."

         2. Intercompany Accounts. Section 6.7 of the Purchase Agreement is
hereby deleted in its entirety and replaced with the following:

            "6.7 Intercompany Accounts. Except for amounts related to normal
            operational sales and cost of sales and fuel, prior to Closing, but
            effective as of the close of business on the last day of


            the month immediately preceding the Closing Date, ONEOK will settle
            all Intercompany Accounts and intercompany arrangements between any
            Entity, on the one hand, and ONEOK and its Affiliates (other than an
            Entity), on the other hand, and the Entities will not have any
            Liability whatsoever with respect to such settled intercompany
            arrangements and Intercompany Accounts. ONEOK shall be solely liable
            for any contractual or other Liabilities, express or implied,
            arising out of the termination, cancellation and elimination of any
            of the foregoing."

         3. Indebtedness for Borrowed Money. Section 6.10 of the Purchase
Agreement is hereby deleted in its entirety and replaced with the following:

            "6.10 Indebtedness for Borrowed Money. Prior to the Closing, but
            effective as of the close of business on the last day of the month
            immediately preceding the Closing Date, (i) ONEOK shall repay or
            otherwise settle any Indebtedness due to the Entities from ONEOK or
            its Affiliates (other than the Entities) and (ii) ONEOK shall cause
            the repayment or settlement of any Indebtedness due from the
            Entities to ONEOK or its Affiliates (other than the Entities), in
            each case, including interest and other amounts accrued thereon or
            due in respect thereof, other than any Indebtedness fully reflected
            in the Closing Working Capital. The Parties acknowledge and agree
            that ONEOK has loaned certain amounts to the Entities after the
            close of business on March 31, 2006 to fund working capital
            requirements of the Entities after such date and that such amounts
            shall be repaid by the NBP Partnerships to ONEOK in the ordinary
            course of business or through the working capital adjustment
            described in Section 1.4 of this Agreement."

         4. Schedule 1.4. The first page to Schedule 1.4 to the Purchase
Agreement is hereby replaced in its entirety by Schedule 1.4 to this Amendment.

         5. Ratification. Except as expressly set forth herein, all other terms
and conditions of the Purchase Agreement shall remain unmodified and in full
force and effect, and the Parties hereby confirm and ratify such terms and
conditions and agree to perform and comply with the same.

         6. Severability. If any provision of this Amendment is invalid or
unenforceable, the balance of this Amendment shall remain in effect.

         7. Counterparts. This Amendment may be executed in any number of
counterparts, each of which will be deemed an original, but all of which
together will constitute one and the same instrument.



         8. Governing Law. This Amendment shall be construed under and governed
by the internal laws of the State of Delaware without regard to its conflict of
laws provisions.




                  [Remainder of Page Intentionally Left Blank]






         IN WITNESS WHEREOF the parties hereto have caused this Amendment to be
executed as of the date set forth above by their duly authorized
representatives.

                                       ONEOK, INC.


                                       By:  /s/ David L. Kyle
                                            ------------------------------------
                                       Name:  David L. Kyle
                                       Title:  Chairman of the Board, President
                                       and Chief Executive Officer



                                       NORTHERN BORDER PARTNERS, L.P.


                                       By:  /s/ William R. Cordes
                                            ------------------------------------
                                       Name:  William R. Cordes
                                       Title:  Chief Executive Officer



                                       NORTHERN BORDER INTERMEDIATE
                                       LIMITED PARTNERSHIP


                                       By:  /s/  William R. Cordes
                                            ------------------------------------
                                       Name:  William R. Cordes
                                       Title:  Chief Executive Officer






                                  SCHEDULE 1.4
                               (Agreed Principles)

For purposes of determining Net Working Capital, the following principles shall
be used:

         o  GAAP: Net Working Capital shall be determined in accordance with
            GAAP, except as set forth below.

         o  Reference Statement: The accounts listed on Exhibit D (the
            "Reference Statement") shall be used in determining Net Working
            Capital, except for those adjustments shown on the Reference
            Statement.

         o  Gas in Storage and Commodity Exchange: The value of the accounts
            entitled "Gas in Storage" and "Commodity Exchange" on the Reference
            Statement shall be determined at market as set forth in Annex 1.4.

         o  Closing Working Capital and Effective Time. The same principles used
            to calculate Target Working Capital (including those set forth in
            this Schedule 1.4 and Annex 1.4 and as reflected in the Reference
            Statement) shall be used to calculate Closing Working Capital,
            except that the "Effective Time" for purposes of calculating Target
            Working Capital shall be close of business on the date of the
            Reference Statement and the "Effective Time" for purposes of
            calculating Closing Working Capital shall be close of business on
            the last day of the month immediately preceding the Closing Date;
            provided that natural gas and natural gas liquids shall be measured
            and valued as of 7:00 a.m. on each of such dates, rather than as of
            the close of business.