Mich. Comp. Laws § 117.27b
When the charter of any city heretofore adopted provides that the city representatives on the board of supervisors of the county shall be members of the city's board of review or act in any other official capacity or perform any other official function, such city may provide by ordinance for the appointment of the members of the board of review of the city from the citizens of the city and for the filling of such other offices and the performance of such official functions heretofore filled or carried out by such city representatives in such manner as the legislative body of such city shall prescribe.
In the years 1969 and 1970 the legislative body of any city whose charter provides for a board of review consisting of appointed members of the county board of supervisors may appoint a board of review consisting of the same number as those now serving as appointed members consisting of electors resident in the city, to review the assessment roll according to law, notwithstanding the provision of any charter or law to the contrary.
MCL 117.27b