And just to expand on
@Lynne M 's point a bit... You will likely never speak to the person who actually switched your reservation. So remember that it's not the fault of the person on the other end of the phone, but they are the person who can possibly help you get what you want.
Having worked customer service for a major tech company in several roles, I can tell you that often I had the ability to pixie dust customers... but when they started off by screaming at me, and telling me how my company and I both sucked, and how stupid I was? I put the pixie dust away, and stayed "by the book" all the way.
Just remember that you are mad at the situation, not the person you are talking to on the phone.