TOPIC: You have already registered for the event

Sorry if this is already a topic. I searched for "You have already registered for the event", but the words were too common.

Would it be too much to ask, if they are already registered to reroute the user to the edit the event page for them (I'm using CB)?

Side question: If an event is open to the public and one can register and pay... How would they later edit their event registration information (WITHOUT a login)?