N.Y. Gen. Oblig. Law § 5-1551
A parent of a minor or incapacitated person may designate another person as a person in parental relation to such minor or incapacitated person pursuant to sections twenty-one hundred sixty-four and twenty-five hundred four of the public health law and sections two and thirty-two hundred twelve of the education law for a period not exceeding twelve months provided that there is no prior order of any court in any jurisdiction currently in effect that would prohibit such parent from himself or herself exercising the same or similar authority, and provided further, that, in the case where a court has ordered that both parents must agree on education or health decisions regarding the child, a designation pursuant to this subdivision shall not be valid unless both parents have consented thereto. Such designation shall be in the form prescribed by section 5-1552 of this title, and may be presented to any school, health care provider or health plan that requires such designation by either the parent or the designee.
N.Y. Gen. Oblig. Law § 5-1551