156. Rectification of mistakes.-

(1)   Any income tax authority or the Appellate Tribunal may amend any order passed by it to rectify any mistake apparent from the record on its own motion or on such mistake being brought to its notice by any other income tax authority or by the assessee.

(2)   No order under sub-section (1), which has the effect of enhancing an assessment or reducing a refund or otherwise increasing the liability of the assessee, shall be made unless the parties affected thereby have been given a reasonable opportunity of being heard.

(3)   Where any such mistake is brought to the notice of any income tax authority by the assessee and no order under sub-section (1) is made by such authority before the expiration of the financial year next following the date in which it was so brought to its notice, the mistake shall be deemed to have been rectified and all the provisions of this Ordinance shall have effect accordingly.

(4)   No order under sub-section (1) shall be made after the expiration of four years from the date of the order sought to be amended.