In DHCP Manager, select the Addresses tab.
See How to Start and Stop DHCP Manager for information about DHCP Manager.
Choose Delete Networks from the Edit menu.
The Delete Networks dialog box opens.
In the Keep Networks list, select the networks that you want to delete.
Press the Control key while you click with the mouse to select multiple networks. Press the Shift key while you click to select a range of networks.
Click the right arrow button to move the selected networks to the Delete Networks list.
If you want to remove the host table entries for this network's DHCP addresses, select Delete Host Table Entries.
Note that deleting host table entries does not delete the host registrations at the DNS server for these addresses. Entries are deleted only in the local name service.