replace 2000 DC with 2003 DC

We have 2 DC’s running Win2000 Server. One is the “primary” DC. We are replacing the “secondary” DC with a new server running Win2003 Server. As I understand things so far, I will have to run adprep /forestprep & adprep /domainprep on the primary DC first.

Questions…
Do I demote the old secondary DC first before running adprep?

Once i demote the old secondary and remove it from the domain and then hook up the new unit that will become the secondary and promote it to be a DC, how do I get Active Directory set up on it?