In DHCP Manager, select the Options tab.
See How to Start and Stop DHCP Manager for information about DHCP Manager.
Select the option that you want to delete.
Choose Delete from the Edit menu.
The Delete Option dialog box opens.
Select Notify DHCP Server of Change if you are finished deleting options.
This selection tells the DHCP server to reread the dhcptab table to put the change into effect immediately after you click OK.