N.Y. U.C.C. 3-115

Section 3--115. Incomplete Instruments.\n (1) When a paper whose contents at the time of signing show that it is\nintended to become an instrument is signed while still incomplete in any\nnecessary respect it cannot be enforced until completed, but when it is\ncompleted in accordance with authority given it is effective as\ncompleted.\n (2) If the completion is unauthorized the rules as to material\nalteration apply (Section 3--407), even though the paper was not\ndelivered by the maker or drawer; but the burden of establishing that\nany completion is unauthorized is on the party so asserting.\n