Completion or Alteration of Instrument

(1) Where a security contains the signatures necessary to its issue or transfer but is incomplete in any other respect (a) Any person may complete it by filling in the blanks as authorized; and (b) Even though the blanks are incorrectly filled in, the security as completed is enforceable by a purchaser who took it for value and without notice of such incorrectness. (2) A complete security which has been improperly altered even though fraudulently remains enforceable but only according to its original terms.