Mich. Comp. Laws § 38.61

Sec. 61. An elected or appointed official who is first elected or appointed on or after March 31, 1997 may irrevocably elect not to become a qualified participant of Tier 2 or may irrevocably elect to discontinue participation in Tier 2 by filing written notice of the election with the state treasurer. Upon receipt of the election, his or her employer shall not contribute any percentage of compensation under section 63 for the official who makes either election.