I'm planning to add two Server 2008 R2 domain controllers into my domain in the next couple of weeks and was wondering how much of the process can be performed during the day while staff is working. I have two Server 2003 SP2 DCs at the moment on a LAN with all static addressing. Both DCs are the DNS servers and the new machines will need to assume the old machine's IP addresses so I don't have to change all of the static DNS settings on my devices. All of the FSMO roles are on DC1 and both machines are global catalogs. The basic plan is to prep the domain (adprep), demote DC2, have DC3 take DC2's IP address then promote it to a DC. I'd then make it a global catalog and transfer the FSMO roles over to it. Lastly I'd repeat the process for DC1. I'm curious if most of this can be done during the day or if these changes would cause problems for staff trying to log in and resolve DNS requests. Let me know what you think, thanks!