Mich. Comp. Laws § 83.3

Sec. 3. No election of aldermen or ward officers shall be held in any newly established ward, or in any ward, on account of changes in the boundaries thereof, previous to the next annual city election; nor shall the office of any alderman or other officer elected in any ward be vacated by reason of any change in such ward; but any such alderman and other officer shall, during the remainder of his term, continue in office and to represent the ward including the place of his residence at the time of the change of the boundaries of the ward, unless the office become vacant for some other cause.