Always had changes after booking with AA and they always put us on another flight. However, we didn't always like the new flights so I'd call them and say it wasn't acceptable and told them what I wanted (after having checked what other connections were available.)
Once, when the lights were out at Julianna I called AA to tell them since our flight was arriving near dusk. They said they couldn't change without a fee so I asked to speak to a supervisor who I told that as we spoke fits were being diverted to PR and AA should know that. She said lights would be fixed by the time of my flight---guess she wasn't familiar with "island time."
After a time on hold I got the change I wanted with no charge. Next day on their web site was an advisory about the problem.
So it pays to always speak to someone if you're not happy.
By the way as I recall it took several days to fix that landing lights problem in SXM.
