End a Callback in a ZCC Queue

We are new to ZCC.  Is it possible as a supervisor or admin on the account to end an engagement that's waiting in a ZCC queue?  We had a situation where there was a callback waiting in the Q that didn't need to be made, but I couldn't find a way to clear it out and the agents couldn't get past it to move on to the next.....  What are the options in a situation like that?