2006 New York Code - Powers, Duties And Limitations

 
  § 11-1.4 Validity  of execution of power to sell, mortgage or lease real
             property by less than all qualifying executors
    Any deed, mortgage or lease duly executed by one or more, but not all,
  of the executors or trustees who qualified conveys the  full  title  and
  interest of the testator, and is as effective as if all the executors or
  trustees  who  qualified  had  joined in the execution thereof, when ten
  years have elapsed since the recording of such deed, mortgage  or  lease
  in  the county where the property affected is situated; saving, however,
  the rights of every grantee, mortgagee or lessee, in good faith and  for
  a valuable consideration, deriving title under an instrument executed by
  all  the executors or trustees who qualified to the same property or any
  part thereof, whose deed, mortgage or lease is duly recorded before such
  period of ten years has elapsed.