The primary user-ID otherwise known as your "Username" for your GoFax account cannot be changed.
The "Username" can be located within your GoFax account on the top right corner of your secure Gofax Dashboard.
Other details including company name, ABN, contact details and email addresses (including the email address associated with the primary account holder) can all be changed.
To change your Account Details see "Managing your account details".
To change your Password see "Resetting your password".