1. Right click on the Superscope and click delete. It’s safe and won't have any impact on the Sub-scopes under this DHCP superscope. In fact you will receive a message that confirms the deletion without impacting or deleting any child scopes as per attached below.
2. One other way is to deactivate the sub-scopes (under your DHCP Superscope), move these scopes and then activate them. After all sub-scopes are moved, the DHCP superscope was removed/deleted automatically.
DHCP Technical Documentation:
- How DHCP Technology Works: http://technet.microsoft.com/en-us/library/cc780760(WS.10).aspx
- DHCP Superscopes: http://technet.microsoft.com/en-us/library/cc757614%28v=WS.10%29.aspx