I was able to book a new package online with Disney before I had AAA cancel my existing package. I did it that way because I booked at about 5:10 PM on Thursday - right after the deal was released! My AAA agent was off Thursday and I didn't want to try to explain what I wanted to someone else over the phone. We were adding an additional day - at the Beginning of our trip. I also wanted to get in on the deal ASAP, just in case what I wanted sold out quickly. I had NO problem booking a ressie online. I left a message for my AAA agent that night, she called me back the next day, no problem at all, and she talked to Disney and they transferred my initial $200 deposit to the new ressie, so now I have $400 down on the trip. I was able to check online that same day (Friday) and could see the other $200 credited.
RE: what the above poster is asking. It may not have been that the OP actually wanted to use a TA. I know for me that was not the case. However, to book a Package with AAA discount, you HAVE to go through AAA, so I did. This new deal was a much better discount for me (saved $577 plus added the extra night), so this was the way to go. I actually prefer booking myself online, I like to be able to check it, etc. And I don't know about other TA's, but "all that work" was about 10 minutes for me. I knew Exactly what I wanted when I went in, she just booked it. Had my agent been working on Thurs, I probably would have had her look into modifying the ressie. But that just wasn't the case. In addition, a AAA membership is a paid thing - not exactly the same as going to another TA that does the work for no $$ from the customer at all.
Just saying the OP may have been in a similar situation. Wasn't really looking to have a TA do the work, just was getting the AAA discount.