In order to renew your Michigan CNA certification, you must have worked, for pay, as a nurse aide performing nursing or nursing-related services, under the supervision of a licensed Registered Nurse for at least eight consecutive hours within the last 24-month period. If you do not meet this requirement, you must retrain and test, and as far as I know, there are NO EXCEPTIONS. I encourage you to contact the Michigan State Nurse Aide Registry at 800-752-4724 in order to get an official answer.