New York Consolidated Laws, Personal Property Law - PEP § 47-d. Cancellation of assignment

Upon the payment or satisfaction of the indebtedness, and upon written demand delivered personally or by registered mail by the assignor, the assignee shall execute and acknowledge or prove, and deliver to the assignor a certificate setting forth that the indebtedness has been paid or otherwise satisfied and discharged.  Such certificate must recite the date of the assignment, the names of the parties thereto, the amount of the original indebtedness, the filing number, the date of filing thereof, including every assignment of said assignment, if any, specifying in the recital of each assignment the date thereof, the names of the parties thereto, the filing date and the serial number thereof.

If for ten days after such demand the assignee fails to mail or deliver such a statement of satisfaction, he shall forfeit to the assignor five dollars, and be liable for all damages suffered.  Upon presentation of such statement of satisfaction the filing officer shall file the same and note the cancellation of the assignment and the date thereof on the margin of the page where the assignments has been entered.