(1) If at any time after a Planning Authority has declared its intention to prepare a Development plan or after a Development plan prepared by a Planning Authority has been sanctioned, the jurisdiction of the Planning Authority is extended by inclusion of an additional area, the Planning Authority shall make a fresh declaration of intention to prepare a Development plan for the additional area; and after following the provisions of this Act for the preparation of a draft Development plan, [prepare a draft Development plan and publish a notice regarding its preparation], for such additional area either separately or jointly with the draft or final Development plan prepared or to be prepared for the area originally under its jurisdiction, and submit it to the State Government for sanction after following the same procedure as is followed for submission of a draft Development plan to the State Government :
Provided that, where a draft Development plan for the additional area requires modification of the final Development plan or where the State Government directs any such modification, the Planning Authority shall revise the final Development plan after following the procedure laid down in section 38 so far as may be relevant.
(2) Where any area is withdrawn from the jurisdiction of a Planning Authority the proposals, if any, made for that area so withdrawn in a Development plan shall also be deemed to be withdrawn therefrom.