Collaborator needs ability for administrators to merge accounts
One fine summer day, "Jane Smith" (sAMAccountName/username == "janesmit") gets married, and changes her name to Jane Johnson. After returning from her honeymoon and going back to work, she logs into...
I agree it would be nice to change in the Web user interface however in the meantime, you should be able to change the login via the command line interface (ccollab admin user edit):