Will American Airlines charge me a lot for switching departing airports?

American Airlines, like most other airlines, will charge you the change fee that applies to your specific ticket, as well as any fare difference between what you paid and what the new ticket costs. The first answer mentions a $150 change fee, which is the usual change fee on restricted domestic tickets on AA. This change fee could be more (particularly on restricted international tickets), but it could also be less than the $150 as well.

Because the factors depend upon the changes you're making and the specifics that are unique to your ticket and your situation, the only ones who can give you any idea of what AA will charge you are AA themselves. You'll probably want to call them as soon as possible to see what your options are, as the price of making the change is likely to only increase the longer you wait.

Yes, at least $150 plus any fare difference.

You would not only get a good answer but you would get the right answer if you call AA an ask........simple.............