I did it a few years ago. It wasn't same day-I think I dropped it off one morning and picked it up 2 days later. I got it the day before we were traveling so it was nerve wracking.
This may have changed, but one weird thing was that when I went through the automated appointment booking thing, it asked if I wanted an afternoon or morning appointment. I said afternoon, and it said the first available date was after I was supposed to travel. I hung up, called back, and chose morning and they had much earlier slots available. Turns out they hardly have any afternoon appointments, it's mostly morning.