I assume you mean your ham license, right?
Go to the FCC Universal Licesning System FCC Universal Licensing System (ULS): ULS Home
Click on "Online Filing Log In" and follow the instructions.
When you get your FRN and password you can change your license details online here. I changed a misspelling in my last name this way. I believe there is a link to the fee chart on the page. If I could remember my password I'd login and be able to help more but it escapes me right now...