Rectification of errors apparent on record allows authorities to correct mistakes within a prescribed period, subject to natural justice. Authority may rectify errors apparent on the face of record in decisions, orders, notices, certificates or other documents on its own motion or when brought to its notice by prescribed officers or the affected person within a limited period; a further outer time limit normally bars rectification thereafter except for purely clerical or arithmetical corrections arising from accidental slips or omissions, and any rectification that adversely affects a person must observe the principles of natural justice.