Tenn. Code § 7-67-107
The charter may, at any time and from time to time, be amended in a manner not inconsistent with § 7-67-105. Any such amendment shall be adopted in the following manner: the board of directors of the authority shall file with the governing body of the municipality with which the application for the creation of the authority was filed an application in writing seeking permission to amend the charter, setting forth the proposed amendment to be made. If that sovereign body, by appropriate resolution, finds and determines that it is wise, expedient, necessary or advisable that the proposed amendment be made and authorizes the amendment to be made, approving the form of the proposed amendment, then the chair of the board of directors of the authority shall execute an instrument embodying the amendment, and shall file the amendment with the secretary of state. The secretary of state shall examine the proposed amendment and, if the secretary of state finds that the requirements of this section have been complied with, the secretary of state shall approve the amendment and accept it for filing in an appropriate book in the secretary of state's office. When such amendment has been so made, filed and approved, it shall become effective.
T.C.A. § 7-67-107