New hire reindeer games...Ran out of FDP and got an all expenses paid overnight in ATL with DH home the next day. Scheduler approved deviate DH but flight was full and couldn't book jumpseat so listed as non rev. One of the FA seats was open 15 min prior but agent couldn't figure out how to book me. She finally gave me boarding pass and I boarded and put away my luggage and talked with Capt and lead FA. At departure time I was asked to deplane since they still couldn't figure out how to close the flight. I am now at Hilton--at least it is warmer than Chicago crew rest (barely). Any thoughts?