Yes, the username is available for users to change from the account settings.
To do so, please follow the below steps:
1. Navigate to the 'Account Settings' page. Click on the 'Usernames and Passwords' button
2. Click 'Users' tab.
2. Select the user you want to edit.
3. Under the 'Details' tab, click the green 'Edit' button.
4. Change the username to another unique value, by entering additional characters, then click 'Update' to save changes.
When changing usernames, it is important to remember that they are supposed to be unique and are never removed from the system to help us maintain the audit trail. This will mean that you cannot use the same username for multiple user profiles. For users who use their email address as a username, please avoid using the same email address for two or more user profiles.
What this also means is that if a user profile is deleted, the attached username at the point of deletion will be blocked off from further use. We can retrieve said username but to avoid doing that, it's always best to change the username slightly just before deleting a username. Please see below for an example: