American Airlines Normally Doesn’t Permit Any Name Changes After a Ticket is Booked, except for very minor spelling corrections or a name change due to marriage. Here are more details you should know about the American Airlines Name Change
You may not be able to fly on a United flight if the name on your ticket does not match your passport name. A small correction may be made without additional charges to the passenger according to United Airlines Name Change Policy.
If you've booked a Delta Airlines ticket but want to change your name after arriving at your destination, you need to know their Delta Airlines Name Change Policy.

https://www.travelintellect.com/american-airlines-name-change-policy/
https://www.travelintellect.com/united-airlines-name-change-policy/
https://www.travelintellect.com/delta-airlines-name-change-policy/