N.Y. Suffolk County Tax Act § 40-d
Before the county treasurer shall cancel a tax sale, pursuant to the provisions of this article, and issue a certificate of cancellation, the party claiming under the tax deed issued from the sale sought to be cancelled, his heirs or assigns, shall deliver to the county treasurer an instrument of abandonment of any and all claims and interest under and by virtue of such tax deed duly executed and acknowledged in the same manner as a deed, which shall not affect his right to a refund, together with satisfactory proof that he has not conveyed the land described in such tax deed or any part thereof or interest therein. At the time of issuing the certificate of cancellation the county treasurer shall transmit such instrument of abandonment to the county clerk. The county clerk shall record such instrument of abandonment in a book of deeds in his office and index the same as though the party executing it were a grantor in a deed.
This section shall not apply to any cancellation of a tax sale and issuance of a certificate of cancellation thereof made on application of one other than the purchaser, his heirs or assigns.
N.Y. Suffolk County Tax Act § 40-d