Mich. Comp. Laws § 500.3204: Refusal to renew policy as cancellation; requisites.

Sec. 3204.

No insurer shall cancel a policy of automobile liability insurance issued after November 1, 1966, in pursuance of their certificate of authority by the department unless the cancellation is effected pursuant to the applicable provisions of this chapter.

Refusal to renew any policy of automobile liability insurance shall not constitute a cancellation unless the insurer fails to mail, 20 days prior to the termination date of the policy, by first class mail, a notice to the insured that the policy will not be renewed.