Probate Court is not involved in the signing stage. If and when a physician or licensed nurse practitioner makes a written determination that a parent or legal guardian who signed such a designation has in fact become unable to care for the minor by virtue of a physical or mental condition, the standby guardianship is activated. At that point, the standby guardian is required to file a Notice of Standby Guardianship, along with a copy of the Designation of Standby Guardian and a copy of the health care determination, in the probate court of the county of residence of the minor. The probate court will file and record the notice and attached copies, but will take no further action unless subsequent proceedings are later filed as described in the next paragraph.

The standby guardianship automatically expires four months from date of the health care determination unless the standby guardian files a petition seeking guardianship of the minor. This would probably most often be a petition seeking temporary guardianship. It would be filed in the court in which the notice was filed. The standby guardian has priority of appointment in the later guardianship proceeding.