My husband and I are flying to Cancun in 2 weeks. When we first booked our trip, Texas was our layover with good seats but we got informed that the flight has changed and now Charlotte is our new layover and our layover time is only 45 mins and we have the last seats on the plane when I say last seats I mean the very back seats at the end of the plane.. Its a small plane with only 23 rows. I decided to upgrade our seats and found 2 seats open in row 11 on AA.com. The problem I am having, I go to AA.com pull up our trip Itinerary click on change seats and pick the seats I want, fill out all the information and click pay now . Then it comes back saying ( System is having trouble check back later). I even called the airlines and got a recording saying to go to AA.com to change our seats. We went through a travel agent and she is on vacation. Is there a reason why I cant change our flight seats. Any advice would be appreciated.