Ex parte disposal of applications permitted; absent parties may seek setting aside and rehearing upon showing sufficient cause. Regulation 19 permits the Authority to dispose of an application ex parte on merits if the applicant or the Principal Commissioner or Commissioner fails to appear on the fixed or adjourned hearing date. If the absent party applies within seven days of receiving the order and shows sufficient cause for non appearance, the Authority may, after giving the opposite party a reasonable opportunity to be heard, set aside the ex parte order and restore the application for fresh hearing.