Mass. Gen. Laws ch. 123 § 3
The department may transfer any person from any facility to any other facility which the department determines is suitable for the care and treatment of such person; provided that no transfer to a private facility shall occur except with the approval of the superintendent thereof. At least six days before a transfer from a facility occurs, the superintendent shall give written notice thereof to the person and to the nearest relative, unless said person knowingly objects, or guardian of such person; provided, however, if the transfer must be made immediately because of an emergency, such notice shall be given within twenty-four hours after the transfer. Except in emergency cases, no person who at any time prior to transfer has given notice of his intention to leave a facility under the provisions of section eleven shall be transferred until a final determination has been made as to whether such person should be retained in a facility.
Mass. Gen. Laws ch. 123, § 3