A real estate broker shall immediately deliver a copy of any instrument to any party or parties executing the same, where such instrument has been prepared by such broker or under his supervision and where such instrument relates to the employment of the broker or to any matters pertaining to the consummation of a lease, or the purchase, sale or exchange of real property or any other type of real estate transaction in which he may participate as a broker.
N.Y. Comp. Codes R. & Regs. Tit. 19 § 175.12