Rectification of advance ruling requires an opportunity to be heard before measures increasing tax liability or reducing input tax credit. The Authority or the Appellate Authority may amend an advance-ruling order to rectify any error apparent on the face of the record, whether noticed suo motu or brought to notice by an officer, the jurisdictional officer, or the applicant/appellant, within the statutory time limit; however, any rectification that would enhance tax liability or reduce admissible input tax credit requires that the applicant or appellant be given an opportunity of being heard.