New York Consolidated Laws, Mental Hygiene Law - MHY § 29.16 Discharge;  certain cases

The director of a facility shall, with respect to any patient admitted to such facility pursuant to section five hundred nine of the executive law or 353.4 of the family court act and article nine or fifteen of this chapter, give immediate written notice to the director of the division for youth and to the mental hygiene legal service when any such patient leaves the facility without the consent of its director.  Such patient shall not be discharged so long as there is a valid order of the family court placing such person with the division for youth, except in accordance with the provisions of section five hundred nine of the executive law or section 353.4 of the family court act.