§ 267. Conveyances with power to revoke, determine or alter. A
conveyance of, or charge on, an estate or interest in real property,
containing a provision for the revocation, determination or alteration
of the estate or interest, or any part thereof, at the will of the
grantor, is void, as against subsequent purchasers and incumbrancers,
from the grantor, for a valuable consideration, of any estate or
interest so liable to be revoked or determined, although the same be not
expressly revoked, determined or altered by the grantor, by virtue of
the power reserved or expressed in the prior conveyance or charge. Where
a power to revoke a conveyance of real property or the rents and profits
thereof, and to reconvey the same, is given to any person, other than
the grantor in such conveyance, and such person thereafter conveys the
same real property, rents or profits to a purchaser or incumbrancer for
a valuable consideration, such subsequent conveyance is valid, in the
same manner and to the same extent as if the power of revocation were
recited therein, and the intent to revoke the former conveyance
expressly declared. If a conveyance to a purchaser or incumbrancer,
under this section, be made before the person making it is entitled to
execute his power of revocation, it is nevertheless valid, from the time
the power of revocation actually vests in such person, in the same
manner, and to the same extent, as if then made.