Commonwealth Consolidated Regulations Commonwealth Consolidated Regulations21.05.1 At any stage of a proceeding the Court or a Justice may order that:
(a) a person who is not then a proper or necessary party cease to be a party;
(b) any person who ought to have been joined as a party or whose presence in the proceedings is necessary to ensure that all questions in the matter are effectually and completely determined be joined as a party; or
(c) any person between whom and any party to the proceeding there may exist a question arising out of or relating to or connected with any claim in the proceeding which it is just and convenient to determine as between that person and the party as well as between the parties to the proceeding be joined as a party.
21.05.2 A person shall not be added as plaintiff without that
person's written consent.