(1) Where a statement of claim is served in a proceeding commenced by writ, the plaintiff may therein alter, modify or extend the claim as indorsed on the writ without amendment of the indorsement.
(2) The Court may, by order, allow the plaintiff to serve a statement of claim the effect of which will be to add a new cause of action to or substitute a new cause of action for a cause of action disclosed in the writ.
(3) Where the Court makes an order under paragraph (2), it may further order that the plaintiff shall amend the indorsement of claim on the writ to make it conform to the statement of claim.