If the Event is coming up relatively soon you can go to your Dashboard. It might be in Your Itinerary, Recent Events, or Upcoming Events sections. If you have gotten an e-mail notification for the event the link to the event would be in there. If it was fairly recent and you have your computer save a history of websites you visited you may be able to get directly back to the event that way but would need to know about when you created it and try different history items until you find it. If none of those are true then I don’t believe there is any other way to get back to that event.
You should watch this other thread as its the same issue and has been updated to PENDING by TT.