Mich. Comp. Laws § 445.613

Sec. 3. After the expiration of the 3-year period set forth in section 2, if a molder chooses to have all rights, title, and interest in a die, mold, or form transferred to the molder by operation of law, the molder shall send written notice by registered mail, return receipt requested, to an address designated in writing by the customer, or if not so designated, to the customer's last known address, indicating that the molder intends to terminate the customer's rights, title, and interest in the die, mold, or form, by having all rights, title, and interest in the die, mold, or form transferred to the molder by operation of law, pursuant to this act.