Mich. Comp. Laws § 767.12: Grand jury; foreman; term, vacancy.

Sec. 12.

The foreman appointed by the court in the manner provided in the preceding section, shall be foreman during the whole time they are required to serve; but in case of his death or absence or if he shall be discharged, or excused before the grand jury shall be dismissed, another of such jurors shall be appointed foreman for the residue of such time of service.