To delete a state, select it and then press the Del key, or click the button on the Event Modeler toolbar. If you selected multiple states, each of these actions deletes all selected states.
When you delete a state, if there are any rules with transitions to the deleted state, Event Modeler changes the transition section of those rules to transition incomplete. This makes the state that contains this rule incomplete. Event Modeler cannot generate EPL for this scenario until you complete the transition for this rule.