N.Y. Mental Hyg. Law § 29.16

§ 29.16 Discharge; certain cases.\n The director of a facility shall, with respect to any patient admitted\nto such facility pursuant to section five hundred nine of the executive\nlaw or 353.4 of the family court act and article nine or fifteen of this\nchapter, give immediate written notice to the director of the division\nfor youth and to the mental hygiene legal service when any such patient\nleaves the facility without the consent of its director. Such patient\nshall not be discharged so long as there is a valid order of the family\ncourt placing such person with the division for youth, except in\naccordance with the provisions of section five hundred nine of the\nexecutive law or section 353.4 of the family court act.\n