Rectification of advance ruling: authority may amend orders to correct apparent errors, hearing required before increasing tax liability. The Authority or Appellate Authority may amend any order to rectify any error apparent on the face of the record, on its own motion or if brought to its notice by the concerned officer, jurisdictional officer, applicant or appellant, within a specified time limit; provided that no rectification that increases tax liability or reduces admissible input tax credit shall be made without giving the applicant or appellant an opportunity of being heard.