Can I change my class-of-service after booking my flight (e.g. move from Economy to Business Class)?

Most airline loyalty programs allow a change in class of service for a fee. It’s helpful to note that you will need to follow the rules of the program you booked through, regardless of which carriers are operating your itinerary.  After booking, check your email confirmation to verify which program you should contact to make changes, or search their website for more information.