Rectification of record errors: authority may correct apparent mistakes subject to time limits and natural justice protections. Authoritys' power to rectify errors apparent on the face of record in any issued decision, order, notice, certificate or other document may be exercised suo motu or on notice from an appointed officer or the affected person, subject to prescribed temporal limits and an exception for purely clerical or arithmetical accidental slips; where rectification adversely affects a person, the authority must follow principles of natural justice.