Rectification of advance ruling permits amendment for apparent errors, but hearing is required before increasing tax liability or reducing input tax credit. The Authority or the Appellate Authority may amend any order passed under the advance ruling provisions to rectify any error apparent on the face of the record if noticed by them or brought to their notice by the concerned officer, jurisdictional officer, applicant, or appellant within the prescribed period; provided that no rectification that enhances tax liability or reduces admissible input tax credit shall be made without giving the applicant or appellant an opportunity of being heard.