1. Click Start, click Run, and then type the following command:
dcpromo /forceremoval
2. Click OK. If Certificate Services is not removed, you will get a message to remove it first. If FSMO roles/GC are not seized from the DC, you will get a message to transfer the roles to another DC.
3. At the Welcome to the Active Directory Installation Wizard page, click Next.
4. At the Force the Removal of Active Directory page, click Next.
5. In Administrator Password, type the password and confirmed password that you want to assign to the Administrator account of the local SAM database, and then click Next.
6. In Summary, click Next.
7. When it finishes, click Finish and reboot the computer.
We Support Windows 2003 thru Windows 2016 Servers – Please let us know if you need individual help