Section 12. Rectification of mistake.

(1) A tax authority may amend any order passed by it under this Act so as to rectify any mistake apparent from the record. (2) No amendment under this section shall be made after a period of four years from the end of the financial year in which the order sought to be amended was passed. (3) The tax authority shall not make any amendment, which has the effect of enhancing the undisclosed foreign income and asset or reducing a refund or otherwise increasing the liability of the assessee, unless the authority concerned has given to the assessee an opportunity of being heard. (4) The tax authority concerned may make an amendment under this section— (a) on its own motion; or (b) on an application made to it by the assessee or, as the case may be, by the Assessing Officer. (5) Any application received by the tax authority for amendment of an order shall be decided within a period of six months from the end of the month in which such application is received by it. (6) In a case where the order has been made in an appeal or revision, the power of the tax authority to amend the order shall be restricted to matters other than those decided in appeal or revision.