Modify Domain name on local Server 2003

Hello,

I have a Server 2003 box that is a member of a NT 4.0 domain at this time.
(No AD installed yet.) I need to know if I can modify the computer name
adding a different domain suffix (Server 2003 with AD installed is the new
domain server I have setup) to it without jeopardizing any of the local
accounts installed on the first local server I mentioned.

To answer an obvious first question: I am not able to make it a member of
the newer 2003 domain at this time, I just want to append the hostname for
now.

Is this possible without losing any account info on the local box?

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Thank you!