N.Y. Lien Law § 14

§ 14. Assignment of lien. A lien, filed as prescribed in this article,\nmay be assigned by a written instrument signed and acknowledged by the\nlienor, at any time before the discharge thereof. Such assignment shall\ncontain the names and places of residence of the assignor and assignee,\nthe amount of the lien and the date of filing the notice of lien, and be\nfiled in the office where the notice of the lien assigned is filed. The\nfacts relating to such an assignment and the names of the assignee shall\nbe entered by the proper officer in the book where the notice of lien is\nentered and opposite the entry thereof. Unless such assignment is filed,\nthe assignee need not be made a defendant in an action to foreclose a\nmortgage, lien or other incumbrance. A payment made by the owner of the\nreal property subject to the lien assigned or by his agent or\ncontractor, or by the contractor of a public corporation, to the\noriginal lienor, on account of such lien, without notice of such\nassignment and before the same is filed, shall be valid and of full\nforce and effect. Except as prescribed herein, the validity of an\nassignment of a lien shall not be affected by a failure to file the\nsame.\n