Once an username has been selected during the onboarding process with Human Resources, username changes are only performed for:

Even with legal name changes, we cannot always change the original username because of dependencies on accounts created in various systems. If there is an operational need we will make a change, e.g. removing a dash in a user id because a system the user needs access to does not accept dashes.

Making changes to usernames may have a negative impact on other systems at the Lab that rely on the original username assigned to a user.