Change fsmo roles then demote old server

Change fsmo roles then demote old server

http://blogs.technet.com/b/canitpro/archive/2015/02/11/step-by-step-migrating-windows-server-2003-fsmo-roles-to-windows-server-2012-r2.aspx      

Then to demote the old one.

  1. On a domain controller, click Start, and then click Run.
  2. In Open, type dcpromo to open the Active Directory Installation Wizard, and then click Next.
  3. On the Remove Active Directory page, click Next, and then continue to follow the wizard.