Mich. Comp. Laws § 408.972: Collective bargaining agreement.

Sec. 12.

(1) If an employer's employees are covered by a collective bargaining agreement in effect on the effective date of this act and the collective bargaining agreement conflicts with this act, this act applies beginning on the stated expiration date in the collective bargaining agreement, notwithstanding any statement in the agreement that it continues in force until a future date or event or the execution of a new collective bargaining agreement.

(2) If an employer's employee is covered by a contract, not including an employer policy signed by the employee, and all of the following requirements are satisfied, this act applies beginning on the stated expiration date in the contract, notwithstanding any statement in the contract that the contract continues in force until a future date or event or the execution of a new contract:

(a) The employer and employee signed the contract on or before December 31, 2024.

(b) The contract is effective for not longer than 3 years.

(c) The contract conflicts with this act.

(d) The employer notifies the department of the contract.

(3) If a small business did not employ an employee on or before February 21, 2022, the small employer is not required to comply with this act until 3 years after the date that the employer first employs an employee.