Business reorganisation: successors must file a modified income-tax return post-order to reflect the order in prescribed form. Section 170A mandates that where a court, tribunal or adjudicating authority issues an order in respect of a business reorganisation and a successor has already filed a return for affected assessment year(s), the successor must, within a prescribed post-order period, furnish a modified return in the prescribed form and manner that is in accordance with and limited to that order. 'Business reorganisation' covers amalgamation, de merger or merger; 'successor' includes all resulting companies whether pre-existing or newly formed.