Reset Administrator username

I have a Windows 2000 server that a member of my dept. changed the name of the admin account. This server has dropped from our domain and I am unable to login as the Admin on the domain. Because of the unknown administrator account name I can not log on locally either. I thought the recovery console would give the option to reset the admin account to its default name, it does not.
The question “Is there a way to change the admin account username to default or just to change it. I do have the password