12. The person executing a declaration that any property shall be held subject to the provisions of this Act may, in such declaration or by a subsequent instrument in writing, signed and attested as aforesaid, and registered, and any successor in interest of such person, in possession of the settled estate and competent to contract, may, by an instrument signed and attested as aforesaid, and registered, provide that any such declaration shall as regards the whole or any specified portion of the settled estate be irrevocable.
<span style="margin-left:15px;"></span><span style="margin-left:15px;"></span><span style="margin-left:15px;"></span><b>12. </b> The person executing a declaration that any property shall be held subject to the provisions of this Act may, in such declaration or by a subsequent instrument in writing, signed and attested as aforesaid, and registered, and any successor in interest of such person, in possession of the settled estate and competent to contract, may, by an instrument signed and attested as aforesaid, and registered, provide that any such declaration shall as regards the whole or any specified portion of the settled estate be irrevocable.<br>