Tennessee Code Title 8. Public Officers and Employees § 8-35-252

(a) The chief governing body of any employer participating in the retirement system pursuant to this part may by resolution, legally adopted and approved by a two-thirds ( 2/3 ) majority of that body, elect to discontinue the base benefit improvement provisions of § 8-36-124 for all employees employed with such employer after the effective date of the resolution. Employees who were employed prior to the effective date of the resolution will continue to be eligible for the base benefit improvement described in § 8-36-124. Such resolution shall set forth the effective date of the discontinuance; provided, that the date shall be on the first day of any quarter following a minimum of three (3) months' notice to the retirement system.

(b) Any resolution to discontinue the base benefit improvement provisions of § 8-36-124 that is adopted pursuant to this section shall be irrevocable and the employer shall not be permitted to elect at a later date to provide the base benefit improvement provisions of § 8-36-124.