I had to reroute our tickets yesterday due to flight delays. I called United Airlines 800 number directly. There were a few signs early on where my radar went up but I was desparate to get home and overlooked them. The biggest sign was when he told me that if my bank declines the charge for the new ticket to inform the bank that the charge is OK. Thankfully my Southwest Airlines tickets were booked while his "fee" did not go through. Take note when you call an official number that it is truly the airline!