2006 New York Code - Defeasance.

 
    §  295. Defeasance. A series or part of a series of sinking fund bonds
  redeemable from the general sinking fund or any additional sinking  fund
  established  pursuant to section two hundred ninety-eight, including any
  covenants  or  other  agreements  relative  thereto,  shall   be   fully
  discharged  and  of  no  further  force  and  effect at such time as (a)
  sufficient  moneys  or  direct  obligations  of  the  United  States  or
  obligations  guaranteed  by  the  United States have been deposited in a
  separate trust account with a bank, trust company  or  other  fiduciary,
  the principal of and/or interest on which will provide sufficient moneys
  to  pay  punctually  when  due  at  maturity  or  prior  to  maturity by
  redemption, in accordance with their terms, all principal of, applicable
  redemption premium, if any, and interest on such sinking fund bonds, and
  irrevocable instructions from the city to such bank,  trust  company  or
  other fiduciary to make payment of such principal, applicable redemption
  premium, if any, and interest with such moneys shall have been given, or
  (b)  such sinking fund bonds, together with interest thereon, shall have
  been paid in full at maturity, or shall have  otherwise  been  refunded,
  redeemed, defeased or discharged.