Mont. Code Ann. § 53-21-163

Within 30 days after a patient is committed to a mental health facility, the professional person in charge of the facility or the professional person's appointed, professionally qualified agent shall reexamine the committed patient and shall determine whether the patient continues to require commitment to the facility and whether a treatment plan complying with this part has been implemented. If the patient no longer requires commitment to the facility in accordance with the standards for commitment, the patient must be released immediately without further order of the court unless the patient agrees to continue with treatment on a voluntary basis. If for sound professional reasons a treatment plan has not been implemented, this fact must be reported immediately to the professional person in charge of the facility, the director of the department, the mental disabilities board of visitors, and the patient's counsel.