My wife and I are flying back home on Cathay from TPE-HKG-JFK in business class we booked with points. We bought my dad a seat in economy on the same exact itinerary to go back with us. My dad has never sat in business class, and would love for him to try, so could I switch my seat with him? Will they allow this? If so, then when is the best time to switch? Have him board using my boarding pass or go to our own seats and then let the flight attendant know we will be switching? Or another way.