One who is authorized to act on behalf of another, such as an executor or a trustee.
A representative is someone who can forward written submissions and written evidence to the Tribunal, contact the Tribunal on the applicant's behalf, and accompany the applicant to any meeting or hearing arranged by the Tribunal. With very limited exceptions, a representative must be a registered migration agent.
Agent, solicitor, appeals advisor or other representative authorized, in writing, to act on behalf of any person in a proceeding. [See Rules of Procedure, Representative, page 2, Rule 1(k)