N.Y. Pers. Prop. Law § 427

§ 427. Buyer's or other obligor's right to cancel. 1. In addition to\nany right otherwise to revoke an offer, the buyer or other person\nobligated for any part of the purchase price may cancel a door-to-door\nsale until midnight of the third business day, or until midnight of the\nseventh business day in the case of a door-to-door sale of a personal\nemergency response service, after the day on which the buyer has signed\nan agreement or offer to purchase relating to such sale.\n 2. Cancellation occurs when written notice of cancellation is given to\nthe seller.\n 3. Notice of cancellation, if given by mail, shall be deemed given\nwhen deposited in a mailbox properly addressed and postage prepaid.\n 4. Notice of cancellation need not take the form prescribed and shall\nbe sufficient if it indicates the intention of the buyer not to be\nbound.\n