Mich. Comp. Laws § 141.439

Sec. 19. (1) A member of the legislative body, the chief administrative officer, an administrative officer, or an employee of a local unit shall not authorize or participate in the expenditure of funds except as authorized by a general appropriations act. An expenditure shall not be incurred except in pursuance of the authority and appropriations of the legislative body of the local unit. (2) The legislative body in a general appropriations act may permit the chief administrative officer to execute transfers within limits stated in the act between appropriations without the prior approval of the legislative body.