N.Y. U.C.C. 3-407

Section 3--407. Alteration.\n (1) Any alteration of an instrument is material which changes the\ncontract of any party thereto in any respect, including any such change\nin\n (a) the number or relations of the parties; or\n (b) an incomplete instrument, by completing it otherwise than as\n authorized; or\n (c) the writing as signed, by adding to it or by removing any\n part of it.\n (2) As against any person other than a subsequent holder in due course\n (a) alteration by the holder which is both fraudulent and\n material discharges any party whose contract is thereby\n changed unless that party assents or is precluded from\n asserting the defense;\n (b) no other alteration discharges any party and the instrument\n may be enforced according to its original tenor, or as to\n incomplete instruments according to the authority given.\n (3) A subsequent holder in due course may in all cases enforce the\ninstrument according to its original tenor, and when an incomplete\ninstrument has been completed, he may enforce it as completed.\n