Is there a way that somebody can create an event for an existing topic? Is there a way I could use for creating this event that merging by an admin would not have been necessary?
In order to make a topic an event (i.e. with date/time/location info), the topic needs to be in the Events category. If it is, any user can use the Edit Wiki feature to add that information. Otherwise, it requires a moderator or an admin to recategorize the topic to Events or to merge two threads into one.