S. 254(2): Appellate Tribunal-Rectification of mistake apparent from the record – Duty of Tribunal to decide on merits – Appeal dismissed ex- parte for non prosecution- Granted liberty for recall of order – Application for recalling the order rejected on ground of limitation – Date of communication or knowledge, actual or constructive, of the orders sought to be rectified or amended under S. 254(2) of the Act becomes critical and determinative for the commencement of the period of limitation- Rejection of rectification is held to be not valid . [ S.254(1) ,Appellate Tribunal) Rules, 1963, R. 24 , 35 ]