when did rascal flatts startWhat time does the performance of rascal flatts start at the rodeo?

so i am going to rascal flatts on thursday at the houston rodeo and the ticket says that it starts at 6 45. does that mean that they perform at that time or is that when when did rascal flatts startthe actual rodeo( the bull riding and stuff) begins?
I asked myself the same thing the first time I went. First they do all the bull riding, horseback riding etc... The awhen did rascal flatts startrtist doesn't hit the stage until maybe 830 or 9. I've never actually checked the exact time but the artist definitely doesn't hit the stage at 645.