As an org administrator, I would like to be able to update a username instead of the current workaround which is to create a brand new user and move all content from the old to the new user.
Use cases:
- A username contains a typo
- Person changing last name
- The organization short name is modified in the org's settings, and several user accounts reference the old short name (e.g. jsmith_myorg should now be jsmith_neworg for clarity)
Workaround details from Esri support: http://support.esri.com/en/technical-article/000011984