Mich. Comp. Laws § 450.2141

Sec. 141. If, under this act or the articles of incorporation or bylaws of a corporation or by the terms of an agreement or instrument, a corporation or the board or any committee of the board may take action after notice to any person or after lapse of a prescribed period of time, the action may be taken without notice and without lapse of the period of time, if at any time before or after the action is completed the person entitled to notice or to participate in the action to be taken or, in case of a shareholder or member, by his or her attorney-in-fact, submits a signed waiver or a waiver by electronic transmission of the requirements.