You may decide to remove the SCP for an existing SharePoint Farm from your Active Directory schema, whether because you want to change the value in the container or you just wanto to remove the marker (in theory, this should happen automatically once the last server is removed from a farm).
Whatever your case is, to remove the SCP you just need to run the following cmdlet:
Set-SPFarmConfig -ServiceConnectionPointDelete
After that, to verify it has been removed properly you can check that the marker in the Active Directory schema has disappeared with ADSI Edit, or running the cmdlet
Get-SPFarmConfig –ServiceConnectionPoint
Albandrod's Memory 