I also learned that if a Travel Agent is managing the reservations, you cannot make any changes to the reservation. Everything has to go through the Travel Agent. In the end, I like having full control over my reservation. For those that used a Travel Agent, I believe there is a form you can complete if you want to take over the reservation.
Another great resource other than this thread is Disboards. The folks over there are really helpful and super knowledgeable with all the tips and tricks to ensure you have a wonderful vacation.
Just like others have echoed here, do your research ahead of time and you will likely have a much more enjoyable vacations.