Originally Posted by js1993

Usually, after an equipment swap, people have their seats reassigned as part of the notification. Perhaps this time AA's systems detected the overbooking and blocked out J from further sales but didn't auto-reassign seats. AA will need to decide who gets downgraded and who doesn't. As someone mentioned above, AA will start calling people to ask about changing flights or accepting a downgrade. If your plans are inflexible, you probably just have to wait for the call — or keep calling until you find someone who can actually assign seats. Hope it works out.