Mich. Comp. Laws § 450.2243: Resident agent; resignation; notice; appointment of successor; termination of appointment of resigning resident agent; registered office of corporation.

Sec. 243.

A resident agent of a domestic or foreign corporation may resign by filing a written notice of resignation with the president or a vice president of the corporation and with the administrator. A corporation shall promptly appoint a successor resident agent after its resident agent has resigned. The appointment of a resigning resident agent terminates when a successor is appointed or 30 days after receipt of the notice by the administrator, whichever first occurs. When a resignation becomes effective under this section, the business or residence address of the resigned agent is no longer the registered office of the corporation.