Tenn. Code § 8-36-921
The general assembly shall have the right to freeze, suspend, or modify benefits, employee and employer contributions, plan terms, and design of the hybrid plan on a prospective basis through amendments to or repeals of chapters 34-37 of this title. Nothing under state law may confer to participants in the hybrid plan an implied right to future retirement benefit arrangements and such participants may not assert the indefinite continuation of the retirement formulas, contribution rates, eligibility ages, or any other provision of the plan; provided, however, that the actuarial value of accrued benefits earned by participants prior to the effective date of any such amendment or repeal shall remain an enforceable right and may not be reduced or otherwise forfeited except by the consent of the participant or in accordance with § 8-36-918. Notwithstanding this section or any other law to the contrary, the cost-of-living provisions of § 8-36-701 shall not be deemed an accrued benefit and may be subject to change pursuant to this section and § 8-36-922.
T.C.A. § 8-36-921