Provided further that an order to the prejudice of any person shall not be passed under this section unless that person has been given a reasonable opportunity to show cause against such order.

Rectification of mistakes Rectification of mistakes.―

1. (1) The appellate authority or the revisional authority may, at any time within three years from the date of an order passed by it on appeal or revision, as the case may be, and the assessing authority may, at any time within three years from the date of any assessment or order passed by it, or its own motion, rectify any mistake apparent from the record of the appeal, revision, assessment or order, as the case may be, and shall, within the like period, rectify any such mistake which has been brought to its notice by an assessee: Provided that no such rectification shall be made which has the effect of enhancing an assessment or reducing a refund unless the assessee has been given a reasonable opportunity of being heard in the matter.
2. (2) Where any such rectification has the effect of reducing the assessment, the assessing authority shall make any refund which may be due to such assessee.
3. (3) Where any such rectification has the effect of enhancing the assessment or reducing a refund, the assessing authority, shall serve on the assessee a notice of demand in the prescribed form specifying the sum payable; and such notice of demand shall be deemed to be issued under section 10 and the provisions of this Act shall apply accordingly.