N.Y. EPTL 11-1.4
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.
N.Y. EPTL 11-1.4