Exhibit 4.10 CERTIFICATE OF AMENDMENT OF CERTIFICATE OF FORMATION OF SITHE PENNSYLVANIA HOLDINGS LLC 1. The name of the limited liability company is Sithe Pennsylvania Holdings LLC. 2. The Certificate of Formation of the limited liability company is hereby amended as follows: The present FIRST paragraph shall be deleted in its entirety and replaced with the following new FIRST paragraph: "FIRST: The name of the limited liability company (hereinafter called the "limited liability company") is: Reliant Energy Mid-Atlantic Power Holdings, LLC" The present SECOND paragraph shall be deleted in its entirety and replaced with the following new SECOND paragraph: "SECOND: The address of the registered office and the name and the address of the registered agent of the limited liability company required to be maintained by Section 18-104 of the Delaware Limited Liability Company Act are: The Corporation Trust Company 1209 Orange Street New Castle County Wilmington, Delaware 19801" IN WITNESS WHEREOF, the undersigned has executed this Certificate of Amendment of Sithe Pennsylvania Holdings LLC this 12th day of May, 2000. Reliant Energy Northeast Generation, Inc., as sole member By: /s/ J. Douglas Divine --------------------- J. Douglas Divine President CERTIFICATE OF FORMATION OF SITHE PENNSYLVANIA HOLDINGS LLC The undersigned, an authorized natural person, FOR THE purposes of forming a limited liability company, under the provisions and subject to the requirements of the State of Delaware (particularly Chapter 18, Title 6 of the Delaware Code and THE acts amendatory thereof and supplemental thereto, and known, identified, and referred to as the "Delaware Limited Liability Company Act"), hereby certifies that: FIRST: The name of the limited liability company (hereinafter called the "limited liability company") is: SITHE PENNSYLVANIA HOLDINGS LLC SECOND: The address of the registered office and the name and the address of the registered agent of the limited liability company required to be maintained by Section 18.104 of the Delaware Limited Liability Company Act are: The Corporation Trust Company Corporation Trust Center 1209 Orange Street Wilmington, New Castle County, Delaware 19801 Executed on December 28, 1998. /s/ George Lofaso ------------------------------ George Lofaso Authorized Person CERTIFICATE OF AMENDMENT OF CERTIFICATE OF FORMATION OF SITHE PENNSYLVANIA HOLIDINGS LLC 1. The name of the limited liabilIty company is Sithe Pennsylvania Holdings LLC 2. The Certificate of Formation of the limited liability company is hereby amended as follows: The present SECOND paragraph shall be deleted in its entirety and replaced with the following new SECOND paragraph: SECOND: The address of the registered office and the name arid address of the registered agent of the limited liability company required to be maintained by Section 18-104 of the Delaware Limited Liability Company Act are: United Corporate Services, Inc. 15 East North Street Dover, Kent County, Delaware 19901 IN WITNESS WHEREOF, the undersigned has executed this Certificate of Amendment of Sithe Pennsylvania Holdings LLC this 31st day of March, 1999. Sithe Mid-Atlantic, Inc., as sole member By: /s/ David L. Tohir --------------------------- Name: David L. Tohir --------------------- Title: President