Post-office restriction: former tribunal members barred from appearing, acting or pleading before the appellate forum. On ceasing to hold office, the President, Vice President or other Member is expressly barred from appearing, acting or pleading before the Appellate Tribunal. The provision functions as a professional conduct restriction intended to preclude advocacy by former officeholders before the same adjudicatory body they once served, regulating post tenure engagement in appellate tribunal proceedings and establishing a clear disqualification from practice before that forum.