Can events arising from a prior action be the foundation for a new action?

A plaintiff must have a cause of action at the time he commences the action. Events arising after an action has been commenced cannot be the foundation for a preexisting action. In Medicine Hat Mall v. Kerrybrooke Development, (Calgary C.A. 10131 and 10270, June 20, 1988) Kerans, J.A., states in part: “This case is further complicated by the lack of proper initiating documents. The order was granted on a motion that expresses itself as an interlocutory motion in the 1984 action. It is trite law that one cannot seek relief in a suit for events arising after the suit has been commenced. This case calls for a new suit and no new suit has been commenced.”