Change of planes and ticketed by AA right? you can always cancel the ticket without penalty and find a new route/date that fit's your needs, check this thread

http://www.flyertalk.com/forum/ameri...solidated.html

keep in mind that AA codeshare flight operated by IB will be difficult to select seats but you can always call IB Plus to select seats and OW Sapphire, is not easy to get their phone number but I was able to do it on a codeshare flight a couple of months ago (exit seat in my case).

Another option is tell the AA agent to select any blocked seat, he will get an error but there is a possibility you will get that seat. Sometimes the 5 digit PNR will work on BA.com (they will give you an internal IB link).