I too cannot stand when the assumption is made by an agent that you are ignorant on the subject. I think what we need to remember is that few people are like "us" here on FT and just do not know as much information. For the most part, the DM agents have been very, very helpful and usually not condescending. I generally make it aware early in the phone call, especially on one where I was making a complicated change, that I am aware of the system by using the fare class of the ticket or "PNR" as the res code. For some reason, using their "language" seems to rid any doubt that I know what im doing.