How can I change a username on Win 7 Home Premium

I have three Win 7 machines in the house and I've recently stoodup a Windows Home Server. On one of the client machines, a Win 7 Home Premium box, I need to change one of the usernames so that it will be consistent with the other machines and the WHS box. Unfortunately I cannot use the Local User Manager MMC snap-in to rename the user. The functionality is blocked on Home Premium. I tried doing remotely but that was also blocked.

Is there another way to change a username on Win 7 Home Premium? A command line tool? Registry hack? Or am I out of luck?

TIA

-Mike