To change an events status - go to Event > Manage Events and click the icons on the left side of the event name.
Public = Event is in public mode and is searchable online. 
Private = Event is not listed online. Only accessible via unique event URL. 
Offline = Event is not listed online and not sellable. 
Canceled = Event is in a canceled state. It will show online but will show that the event is canceled status. 