Beertrain

I booked a flight for the middle of Feb with a companion pass with 1 friend. Can I book a later flight with a different friend before going on the 1st trip?

I am going to Austin in February and need a good place to take my girlfriend to hog hunt. I’m looking into the 3 hr options. We are going with friends to Austin so we only have a shorter amount of time to go out. Does anyone have any suggestions?