Not sure what happened to OP, but when I call AA to make a change, I feed the agent the new flights and it takes the agent about 30 seconds to verify that what I am asking for really is there and is correct. Nothing to look up if you've got the details.

Ticketing is still in the dark ages and many of the rules are still based on paper tickets with flight coupons, even though they are no longer relevant for most.

At least AA can issue a ticket online and in fairly short order. Try BA and you will find the 3-day wait for a ticket maddening.