changes in general economic conditions

Exhibit 2.2

December 29, 2009

Quicksilver Gas Services LP
Cowtown Pipeline Partners L.P.
777 West Rosedale Street
Fort Worth, Texas 76104

Reference is hereby made to that certain Purchase and Sale Agreement executed on December 10, 2009 (the “PSA”), by and among Cowtown Pipeline L.P., a Texas limited partnership (“Seller”), and Quicksilver Gas Services LP, a Delaware limited partnership (“KGS”), and Cowtown Pipeline Partners L.P., a Texas limited partnership (“Cowtown”, together with KGS hereinafter referred to as “Purchasers”). In connection with the transactions contemplated under the PSA, this letter will evidence the agreement of Seller and Purchasers that (a) the reference to “December 29, 2009” in Section 9.1(a) of the PSA shall be deleted and replaced with “January 6, 2010”, and (b) the Termination Date referenced and defined in Section 10.1(b) shall changed from “December 31, 2009” to “January 30, 2010”. Except as otherwise provided herein, the PSA shall continue in full force and effect in accordance with its original terms. This letter may be executed in counterparts, each of which shall be deemed an original instrument, but all such counterparts shall constitute but one agreement.