New York Consolidated Laws, Real Property Law - RPP § 305. Compelling witnesses to testify

On the application of a grantee in a conveyance, his heir or personal representative, or a person claiming under either of them, verified by the oath of the applicant, stating that a witness to the conveyance, residing in the county where the application is made, refuses to appear and testify concerning its execution, and that such conveyance can not be proved without his testimony, any officer authorized to take, within the state, acknowledgment or proof of conveyance of real property may issue a subpoena, requiring such witness to attend and testify before him concerning the execution of the conveyance.  A subpoena issued under this section shall be regulated by the civil practice law and rules.