A conveyance or charge of or upon an estate or interest in land containing a provision for the revocation, determination, or alteration of the estate or interest, or a part of it, at the will of the grantor, is void as against subsequent purchasers from the grantor for a valuable consideration of an estate or interest liable to be revoked or determined, although the estate or interest is not expressly revoked, determined, or altered by the grantor by virtue of the power reserved or expressed in a prior conveyance or charge.