**Exhibit 10.6**

 

**AMENDMENTNO. 1 TO THECREDIT AGREEMENT**

 
|   | Dated as of March 31, 2006 |
|--------|----------------------------|

 

**AMENDMENT NO. 1 TO THECREDIT AGREEMENT** among TC PipeLines, L.P., aDelaware limited partnership (the “Borrower”), the banks, financialinstitutions and other institutional lenders parties to the Credit Agreementreferred to below (collectively, the “Lenders”) and Citicorp NorthAmerica, Inc., as agent (the “Agent”) for the Lenders.

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**PRELIMINARY STATEMENTS:**

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**(1)**           TheBorrower, the Lenders and the Agent have entered into a Credit Agreement datedas of March 31, 2006 (the “Credit Agreement”). Capitalized terms nototherwise defined in this Amendment have the same meanings as specified in theCredit Agreement.

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**(2)**                                  TheBorrower and the Required Lenders have agreed to amend the Credit Agreement ashereinafter set forth.

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**SECTION 1.  Amendmentsto Credit Agreement.  **The CreditAgreement is, effective as of the date hereof and subject to the satisfactionof the conditions precedent set forth in Section 3, hereby amended asfollows:

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**The definition of “Adjusted Cash Flow” inSection 1.01 is amended by adding at the end thereof the followingsentence “For purposes of calculating Adjusted Cash Flow for any period, ifduring such period the Borrower or any Subsidiary shall have made an acquisition,Adjusted Cash Flow for such period shall be calculated after giving pro formaeffect thereto as if such acquisition had occurred on the first day of suchperiod, including, without duplication, all cash dividends and otherdistributions of cash the Borrower or such Subsidiary would have received ifsuch acquisition had occurred on the first day of such period.**

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**SECTION 2.  Acknowledgement of Corrections.  By execution below, the parties heretoacknowledge that the Effective Date of the Credit Agreement was March 31, 2006and, contrary to the terms of the Credit Agreement, the Borrowing was made on adate subsequent to the Effective Date. Accordingly, the following provisionsare acknowledged to be corrected as follows:**

 

### **(a) Section 2.01 is corrected by deleting the phrase “on the EffectiveDate” and substituting therefor the phrase“on any Business Day during the period from the Effective Date to April 5, 2006”.**

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### **(b) Section 2.03(a) is corrected to read in full as follows:**

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# **(a)**                                  Commitment Fee. The Borrower agrees topay to the Agent for the account of each Lender a commitment fee on theaggregate amount of such Lender’s unused Commitment from the Effective Dateuntil the date of the Borrowing at a rate per annum equal to the ApplicablePercentage in effect from time to time, payable in arrears quarterly on thelast day of each March, June, September and December, commencing June 30, 2006,and on the date of the Borrowing.

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**SECTION 3.  Conditions of Effectiveness.  This Amendment shall become effective as ofthe date first above written when, and only when, the Agent shall have receivedcounterparts of this Amendment executed by the Borrower and all of the Lendersor, as to any of the Lenders, advice satisfactory to the Agent that such Lenderhas executed this Amendment. This Amendment is subject to the provisions ofSection 8.01 of the Credit Agreement.**

 

**SECTION 4.  Representations and Warranties of theBorrower.  The Borrowerrepresents and warrants as follows:**

 

### **(a)**       The Borrower is a limited partnership dulyorganized, validly existing and in good standing under the laws of  the jurisdiction indicated in the recital ofparties to this Amendment.

 

### **(b)**       The execution, delivery and performance bythe Borrower of this Amendment and the Credit Agreement, as       amended hereby, are within the Borrower’scorporate powers, have been duly authorized by all necessary corporate actionand do not contravene (i) the Borrower’s or the General Partner’sorganizational documents, (ii) any material law or any materialcontractual restriction binding on or affecting the Borrower.

 

### **(c)**       No material authorization or approval orother action by, and no notice to or filing with, any governmental authority orregulatory body or any other third party is required for the due execution,delivery or performance by the Borrower of this Amendment or the CreditAgreement, as amended hereby.

 

### **(d)**       This Amendment has been duly executed anddelivered by the Borrower. This Amendment and the Credit Agreement, as amendedhereby, are legal, valid and binding obligations of the Borrower, enforceableagainst the Borrower in accordance with their respective terms, except asenforceability may be limited by applicable bankruptcy, insolvency,reorganization, moratorium or similar laws affecting the enforcement ofcreditors’ rights generally and by general equitable principles (whetherenforcement is sought by proceedings in equity or at law)..

 

### **(e)**       There is no pending or, to the knowledge ofthe Borrower, threatened action, suit, investigation, litigation or proceeding,including, without limitation, any Environmental Action, against the GeneralPartner, the Borrower or any of its Subsidiaries (other than the DisclosedLitigation) before any court, governmental agency or arbitrator that purportsto affect the legality, validity or enforceability of this Amendment and theCredit Agreement, as amended hereby, or any Note or the consummation of thetransactions contemplated hereby this Amendment and the Credit Agreement, asamended hereby.

 

**SECTION 5.  Reference to and Effect on the CreditAgreement and the Notes.  (a)  On and after the effectiveness of thisAmendment, each reference in the Credit Agreement to “this Agreement”, “hereunder”,“hereof” or words of like import referring to the Credit Agreement, and eachreference in the Notes to “the Credit Agreement”, “thereunder”, “thereof” orwords of like import referring to the Credit Agreement, shall mean and be areference to the Credit Agreement, as amended by this Amendment.**

 

**(b)**         TheCredit Agreement and the Notes, as specifically amended by this Amendment,  are and shall continue to be in full forceand effect and are hereby in all respects ratified and confirmed.

 

**(c)**          Theexecution, delivery and effectiveness of this Amendment shall not, except asexpressly provided herein, operate as a waiver of any right, power or remedy ofany Lender or the Agent under the Credit Agreement, nor constitute a waiver ofany provision of the Credit Agreement.

 

**SECTION 6.  Costs and Expenses.  The Borrower agrees to pay on demandall costs and expenses of the Agent in connection with the preparation,execution, delivery and administration, modification and amendment of thisAmendment and the other instruments and documents to be delivered hereunder(including, without limitation, the reasonable fees and expenses of counsel forthe Agent) in accordance with the terms of Section 8.04 of the CreditAgreement.**

 

**SECTION 7.  Execution in Counterparts.  This Amendment may be executed in any numberof counterparts and by different parties hereto in separate counterparts, eachof which when so executed shall be deemed to be an original and all of whichtaken together shall constitute but one and the same agreement. Delivery of anexecuted**

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**counterpartof a signature page to this Amendment by telecopier shall be effective asdelivery of a manually executed counterpart of this Amendment.**

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# **SECTION 8. Governing Law.  This Amendment shall be governed by, andconstrued in accordance with, the laws of the State of New York.**

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**IN WITNESSWHEREOF, the parties hereto have caused this Amendment to be executed by theirrespective officers thereunto duly authorized, as of the date first abovewritten.**

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|    | TC PIPELINES, LP                              |
|---------|-----------------------------------------------|
|    | By its General Partner TC PipeLines GP,  Inc. |
|    |                                          |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|    |                                          |
|    | CITICORP NORTH AMERICA, INC.,                 |
|    | as Agent and  as Lender                       |
|    |                                          |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|    |                                          |   |
| Lenders |
|    |                                          |
|    | UBS LOAN FINANCE LLC                          |
|    |                                          |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|    |                                          |   |
|    |                                          |   |
|    | MIZUHO CORPORATE BANK, LTD.                   |
|    |                                          |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|    |                                          |
|    |                                          |
|    | THE BANK OF TOKYO-MITSUBISHI UFJ, LTD.,       |
|    | HOUSTON AGENCY                                |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|    | SUNTRUST BANK                                 |   |
|    |                                          |
|    | By                                            |   |   |
|    | Title:                                        |
|         |                                               |  |  |  |  |  |  |

 

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### **SIGNATURES**

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Pursuant to the requirements of the Securities and Exchange Act of1934, the Registrant has duly caused this report to be signed on its behalf bythe undersigned thereunto duly authorized.

 
| ** **              | **TC PipeLines, LP**              |
|-------------------------|-----------------------------------|
|                    | (a Delaware Limited  Partnership) |
|                    |                              |
|                    | By:                               | TC PipeLines GP, Inc.,  its general partner |
|                    |                              |   |
|                    | By:                               | /s/ Russell K. Girling |   |
| Date:  May 4, 2006 |                              | Russell K. Girling |
|                    |                              | Chief Financial Officer (duly authorized officer) |
|                    |                              |   |
|                    | By:                               | /s/ Amy Leong |   |
| Date:  May 4, 2006 |                              | Amy Leong |
|                    |                              | Controller (duly authorized officer) |
|                         |                                   |  |  |  |

 

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