Question : Re-install windows 2003 and restore Primary Domain Controller functions

We recently upgraded out Windows 2003 from standard to an enterprise trial version to verify if we needed the features of enterprise running in our network.  Well, unfortunately, it didn't give us what was expected and we need to revert back to our 2003 standard being that is the license we hold

Is there a way to revert or how can I format, re-install and bring back that server as the PDC.

We are running exchange 2007 within this domain.
We have a secondary domain controller that is up and functional.

Can I take the PDC off-line and let the BDC take over ->  Rebuild the server with 03 standard, join the domain being it's already there and then make the server the PDC?

Look forward to any responses.

Answer : Re-install windows 2003 and restore Primary Domain Controller functions

There is no way you can go back without having to do a re-install.

You will need to move the FSMO roles to the other DC, make sure that the other DC is also a global catalog server, DNS and DHCP etc if appropriate, then demote the enterprise DC, remove it from the domain, re-install windows, promote it back to a DC and then move the FSMO roles back (if required).