Any person who, immediately before the appointed day, is an advocate entitled to practise in the High Court of Assam and Nagaland or in the Court of the Judicial Commissioner for Manipur or in the Court of the Judicial Commissioner for Tripura and was authorised to appear or to act in any proceedings transferred from the said High Court or Courts of the Judicial Commissioners to the common High Court under section 40, shall have the right to appear or to act, as the case may be, in the common High Court in relation to those proceedings.