Have had to deal with United a number of times. Horrible customer service. Step-daughter used to fly to Denver to see her daughter. They let her father change the flight even though her mother paid for the ticket. Nightmare. Once had to change a flight due to military function. Presented military orders. They still charged me to change flight. Tried to work it out with customer service. Was told I'd be refunded but never heard from them again. Delta let my wife change a flight with no questions asked. Not sure how they stay in business. Unaccompanied minor fee is a joke. We fly with other carriers every chance we get.