AFTER the final payment, FBC charges $200 for any kind of change you request. Most US carriers do not charge change fees assuming you don't book their "basic" fare. Generally speaking, to redeem points/miles, you have to book directly with the airline, you can't redeem your Delta miles on other TA sites like Expedia, either. It seemed after the restart they had some $50 and $100 off coupons but I haven't seen those since 2021