How can I change my adobe digital authorization code.

I uninstalled adobe digital editions and reinstalled it. I was never given a prompt to put in an authorization ID. And when I looked at the newly installed digital editions' authorization ID, it was my  old one that I put in the first time I installed the program a few years ago. I do not want to keep the same ID. I have changed my email and I want to use my new email as my authorization ID. Otherwise I can't download books to my reader.