Rectification of errors apparent on the face of record lets authorities correct errors within time limits and with natural justice. An issuing authority may rectify errors apparent on the face of any decision, order, notice, certificate or other document on its own motion or when notified by specified officers or the affected person within three months of issue; no rectification after six months except for clerical or arithmetical corrections arising from accidental slips or omissions; any rectification adversely affecting a person must respect principles of natural justice, and the power is exercisable without prejudice to section 160 and notwithstanding other provisions of the Act.