Originally Posted by formeraa

Schedules are firmed at 90 days out. So, I would advise the OP to wait a couple of weekends (when schedule changes are normally run) before asking to change days and/or airports. A later MIA-DFW flight may be added. In a couple of weeks, I would call in and politely request a change to the next day and/or to FLL -- most agents will help facilitate a reasonable request.