I have a box in my organization that was built by a consultant for my company before I arrived as a DC and a 2003 Exchange box (yes I know not even close to a microsoft best practice).
We've since migrated all of our email off of it, and moved the FSMO roles off of it(it was the first dc and first exchange server in this organization). The next/last thing to get off of it is DHCP which I'll address shortly.
After that how should I tackle this thing? Should I dcpromo it to make it a member server, THEN uninstall Exchange from it, then retire it, or should I uninstall exchange first, then dc promo it?