Rectification of advance ruling: orders may be amended to correct apparent errors, with hearing if tax or input credits are affected. Section 102 authorizes the Authority or Appellate Authority to amend orders under sections 98 or 101 to rectify errors apparent on the face of the record, whether noticed by the Authority itself or brought to its attention by the concerned officer, jurisdictional officer, applicant or appellant, within a prescribed time; proposed rectifications that increase tax liability or reduce admissible input tax credit require giving the applicant or appellant an opportunity of being heard.