N.Y. GOB Law § 5-1507

§ 5-1507. Signature of agent. 1. (a) In any transaction where the\nagent is acting pursuant to a power of attorney and where the\nhand-written signature of the agent or principal is required, the agent\nshall disclose the principal and agent relationship by:\n (1) signing "(name of agent) as agent for (name of principal)"; or\n (2) signing "(name of principal) by (name of agent), as agent"; or\n (3) any similar written disclosure of the principal and agent\nrelationship.\n (b) A third party shall incur no liability for accepting a signature\nthat does not meet the requirements of this subdivision.\n 2. When the agent engages in a transaction on behalf of the principal,\nthe agent is attesting that:\n (a) the agent has actual authority to engage in the transaction;\n (b) the agent does not have, at the time of the transaction, actual\nnotice of the termination or revocation of the power of attorney, or\nnotice of any facts indicating that the power of attorney has been\nterminated or revoked;\n (c) if the power of attorney is one which terminates upon the\nprincipal's incapacity, the agent does not have, at the time of the\ntransaction actual notice of the principal's incapacity, or notice of\nany facts indicating the principal's incapacity.\n (d) the agent does not have, at the time of the transaction, actual\nnotice that the power of attorney has been modified in any way that\nwould affect the ability of the agent to engage in the transaction, or\nnotice of any facts indicating that the power of attorney has been so\nmodified.\n 3. The attestation of the agent pursuant to subdivision two of this\nsection is not effective as to any third party who had actual notice\nthat the power of attorney had terminated or been revoked prior to the\ntransaction.\n