Accidentally Renamed Default-First-Site-Name

[Andrew LaPierre]

Ok, so it wasn't an accident, but it seemed so harmless!

I had an old Samba4 DC that I was testing to go production with but never
flipped the switch. I have time to make the switch now so I figured it
would be good to start with a clean, updated server. I setup a new Ubuntu
14.04 server, joined it to the domain and replicated everything over.

Things were running smoothly until I wanted to demote the old server. I
tried transferring the FSMO roles but they wouldn't move, I eventually shut
down the old server and seized the roles successfully. According to the
wiki, there is no way to demote an offline server using Samba4 so I had to
use Windows tools. I started following a guide to clean up the metadata
from Microsoft. I opened the Active Directory Sites and Services, noticed
the ugly name of "Default-First-Site-Name" and thought I should name that
something different. Well...apparently that's a bad idea (why does
Microsoft allow me to do such a dangerous thing without even a warning??)
So now I can't get onto anything, is there a way to change that name back
to "Default-First-Site-Name" through the terminal?

Thanks for your help!!