My husband and I have flight credit dollars that can ONLY be used for travel for the two of us. And it's a big amount. We are taking my daughter and her best friend to Ireland next summer after their high school graduation, as a gift. We have enough flight miles to book their 2 seats in economy, and enough credit to book ours in 1st class. Once we get to the plane, are we allowed to switch seats and let the girls have the first class seats? I know, you all think we're crazy! But this is THEIR gift and the only reason we are having to go along on THEIR grad trip is because they are both young graduates at 17 yrs old and can't rent cars or check into hotels themselves! Thanks in advance!