N.Y. Comp. Codes R. & Regs. tit. 14, § 22.3 – When patient may sign legal instrument.

(a) No patient shall be permitted to sign any bill, check, draft or other evidence of indebtedness, to make a will, or to execute any contract, deed, mortgage, or other legal conveyance, until after the director or officer in charge of the facility has made a determination that the patient has the mental capacity and willingness to execute the instrument. The facts and circumstances surrounding such transaction, including the document to be executed by the patient shall be carefully scrutinized by the director or officer in charge who shall also interview or cause the patient to be interviewed by a staff physician for the purpose of determining:
1. (1) whether the patient has sufficient mental capacity to understand the transaction and does understand the nature and consequences of his act in executing and issuing the instrument, and
2. (2) whether the patient is willing to sign and execute the instrument.
(b) If the determination is that the patient has the mental capacity and is willing to execute the instrument and if the patient does not have a committee, conservator, or guardian, the director or officer in charge shall permit the patient to execute the instrument and shall enter or cause to be entered in the patient's case record a descriptive note of the transaction and a certification by the interviewing physician that, in his opinion, the patient:
1. (1) understood the nature and consequences of his act in signing and executing the instrument;
2. (2) was willing to sign and execute the instrument.
(c) If the patient has a committee, conservator, or guardian or if the determination is that the patient does not have the mental capacity or the willingness to execute the instrument, the patient shall not be permitted to execute the instrument except upon order of a New York State court of record or of a Federal court, which order shall show that the court had notice of the fact that the person whose signature is sought to be obtained was at the date of the order a patient.
(d) Nothing in this Part shall prevent a patient from being permitted to endorse a check if the money is to be deposited in a bank account in his own name or, in the case of a State facility, in an account in his name in the business office of the facility.