I have a production domain, let's call it PROD.
There is just one PDC(PROD_DC) in the domain and is running some old legacy
system. Recently I found that the PDC's hardware seems to have some problem
and may breakdown at any time. I need to migrate the system to another
server. The primary concern is the user information in the DC so I would like
to build a BDC to replicate the user information. Then obsolate the old DC
and rename the DC to the original computer name.

Since I cannot make any changes to the production environment, I have to
build another NT server in a separate network. As it cannot touch the
production server at installation, I have to built the server as a PDC with
the same domain name PROD. I name the server NPROD_DC.

Here is the problem. Is it possible to make the NPROD_DC a BDC of the
production domain PROD?? Their domain name is now the same but I know that
the SID for the domain is different. Is there anyway I can make production
domain to recognize the NPROD_DC so that I can replicate the user information
to the NPROD_DC? Say, may be change the SID of the new domain? Thank you.

ps. I tried this approach because the KMS in my company describes of this
method. The author claimed that he did built a server using this approach.
However, it's a pity that the document didn't go deep into the steps that I
cannot figure out how he do it. Of course the author have quit the company so
I have to figure it out myself.

Any would be appreciated! thanks~~~