Mich. Comp. Laws § 41.726

Sec. 6. (1) When a special assessment roll is reported by the supervisor to the township board, the assessment roll shall be filed in the office of the township clerk. Before confirming the assessment roll, the township board shall appoint a time and place when it will meet, review, and hear any objections to the assessment roll. The township board shall give notice of the hearing and the filing of the assessment roll as required by section 4a. (2) A hearing under this section may be adjourned from time to time without further notice. A person objecting to the assessment roll shall file the objection in writing with the township clerk before the close of the hearing or within such further time as the township board may grant. After the hearing the township board, at the same or at a subsequent meeting, may confirm the special assessment roll as reported to the township board by the supervisor or as amended or corrected by the township board; may refer the assessment roll back to the supervisor for revision; or may annul it and direct a new roll to be made. (3) If a special assessment roll is confirmed, the township clerk shall endorse on the assessment roll the date of the confirmation. After the confirmation of the special assessment roll, all assessments on that assessment roll shall be final and conclusive unless an action contesting an assessment is filed in a court of competent jurisdiction within 30 days after the date of confirmation.