[Settings] Is there a simple way to change my user name?

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http://www.kubuntuforums.net – I am the only user of my Kubuntu 13.04, so have admin access. Is there a GUI-based way to change my user name? Or a simple CL command? I've had a look at the User Management Application in System Settings, but there's no obvious step, and I'm loath to start meddling in the unknown. Done too much damage that way, in the past.... Cheers (HowTos)