ADDS roles can be removed by using the GUI and Powershell. Powershell is a fast and easy method that requires only a single command.
Remove ADDS Role with PowerShell
Step 1: Open PowerShell.
Step 2: Type in the following command and then press enter:
Uninstall-ADDSDomainController -DemoteOperationMasterRole -RemoveApplicationPartition
Step 3: Provide the local administrator password and press enter.
Step 4: It could take up to 5 minutes. The server will be restarted upon completion.