Mich. Comp. Laws § 38.1381a

Sec. 81a. (1) Notwithstanding section 81, a member may retire with a retirement allowance computed according to section 84(1) if all of the following apply: (a) The member files a written application with the retirement board within the early retirement effective period requesting a retirement allowance effective date that is on or before July 1, 1989. (b) On the last day of the month immediately preceding the retirement allowance effective date stated in the application or the last day of the early retirement effective period, whichever occurs earlier, the member's combined age and length of credited service is equal to or greater than 80 years and the member has 10 or more years of credited service. (c) The member was working as a public school employee immediately preceding the retirement allowance effective date. (2) The reduction provided for in section 84(2) shall not apply to a person who retires pursuant to this section. (3) For purposes of this section, "early retirement effective period" means the period beginning on January 1, 1986 and ending at midnight on January 1, 1989.