Remove a Computer from a Domain
Locally, a computer can be removed from a domain by following the procedures in the "Joining a computer to a Domain or Workgroup" subsection to change the computers membership from a workgroup to a domain.
Use the following procedures to remotely remove a computer from a domain.
Log on to a Domain Controller using an authorized administrator account.
Open the Active Directory Users and Computers tool.
Select Computers. A list of computer objects will appear in the right hand pane.
Right-click on the computer to be removed and select Delete from the menu to remove the computer from the domain.