Mont. Code § 37-3-310
When a person applies for a license of any type to practice medicine in this state, the person shall designate in the application the person's correct and official address to which the department shall send communications, notices, orders, citations, or other process, if any, affecting the person. A person licensed to practice medicine in this state shall keep the department advised at all times of the person's correct mailing address and of the person's correct name. If the person changes the person's address or when the name of a licensee is changed by marriage or otherwise, the person shall within 30 days notify the department electronically or in writing of the old and new address or of the former name and new name. This information must be entered promptly by the department in the official records of the department.
§ 37-3-310, MCA