You can't change your Cherry.tv username. That name is fixed in the database.
But, you can change your display name -- this is the name that viewers see when they look at your stream or read the About Me section below the streaming window. This can be your real name, a nickname or a copy or your username.
Changing the display name
To change your display name (and e-mail address if you want):
Click the profile icon in the top right corner of the screen.
Select My Account.
Go to the Profile tab and update your display name.
Go to the E-mail tab to update the current email address.
That's it.
Now you know how to update your display name and email address.