Michigan Compiled Laws, Chapter 45. Counties § 45.573

(a) After a period of 4 years from the date an optional unified form of county government originally becomes effective, the board of county commissioners of the county, by a 2/3 vote of those members elected and serving, may abolish the form and elect to be governed by the provisions of the general county law then in force. The abolition then shall be submitted to the electorate of the county for approval or disapproval at the next regular primary or general election occurring within the county. If a majority of votes cast on the proposal at the election approve the abolition, the optional unified form of county government shall be abolished in the county effective 180 days after the date of the election.

(b) Upon adoption by the voters of the county of a home rule charter.

(c) After a period of 4 years from the date an optional unified form of county government containing alternate A or alternate B originally becomes effective, if the board of county commissioners of the county does not exercise its discretion to abolish the form, a petition, signed by registered electors of the county equal to not less than 10% of the total number of persons voting in the last previous election for which votes were cast for governor, may be filed with the clerk-register or clerk requesting abolition of the form. Upon the clerk-register or clerk certifying to the board that a proper petition has been filed, the board shall submit the question of abolishing the optional unified form of county government to the electorate of the county for approval or disapproval at the next regular primary or general election occurring within the county. If a majority of votes cast on the proposal at the election approve the abolition, the optional unified form of county government shall be abolished in the county effective 180 days after the date of the election.