Tenn. Code § 49-1516
Upon verification of the statements of service, the board of trustees shall issue prior service certificates certifying to each member the period of service rendered in Tennessee prior to the establishment of the retirement system, with which the member is credited on the basis of his statement of service. So long as membership continues a prior service certificate shall be final and conclusive for retirement purposes as to such service; provided, however, that any member may, prior to July 1, 1959, request the board of trustees to modify or correct his prior service certificate based upon evidence filed prior to July 1, 1959.
When membership ceases, such prior service certificate shall become void. Should the teacher again become a member, such teacher shall enter the system as a teacher not entitled to prior service credit except as provided in § 49-1549 and § 49-1518.
T.C.A. § 49-1516