Originally Posted by
mvoight
Actually, doing number 1 might be a problem as they already have a ticket for the flights, as it sound like the flights which are $30 less are the flights AA has booked them on.
So, it seems they would have to cancel first, before rebooking the same flights for $30 less. Maybe a call to AA would have a nice agent able to property credit them for the fare difference as they were put on a lower cost booking.
My experience with AA is that while it has efficient software to detect duplicate and "impossible" bookings, that the software does a sweep rather than a block. E.g., you can book whatever you want, but it will be found out in due course. If you book a new ticket and then relatively quickly cancel the original ticket, it is unlikely that the software catches it.
If it were to become a problem, e.g., the system blocked OP from purchasing a new ticket, one would then have to call in and have an agent handle the transaction.
Either way, if the $30 cheaper fare remains available today, OP would bet out $30 better off. On the other hand, if he wants to book UA and then cancel AA, that is fine too. Same sequence. Don't cancel the original ticket until you know that the fare for the second ticket remains.