Mich. Comp. Laws § 45.323: Prosecuting attorney; oath of office, filing; delivery of commission.

Sec. 123.

The person so appointed shall, before entering upon the duties of his office, and within 20 days after receiving notice of his appointment, appear before the county clerk and take and subscribe the oath of office prescribed by the constitution, and file the same with the clerk, who shall thereupon deliver to the person so appointed the commission received by him for such person, and shall thereupon give notice to the secretary of state of the filing of such oath, and of the time of filing the same.