In DHCP Manager, select the Macros tab.
All macros that are defined for this DHCP server are listed in the left pane.
See How to Start and Stop DHCP Manager for information about DHCP Manager.
Select the network macro whose name matches the network configuration that you are changing.
The network macro name is the network IP address.
Choose Properties from the Edit menu.
The Macro Properties dialog box displays a table of the options included in the macro.
Select the option that you want to modify.
The option name and its value are displayed in text fields near the top of the dialog box.
(Optional) Modify the option name, or choose the Select button to display a list of option names.
The Select Option dialog box displays a list of all DHCP standard options, with a brief description of each option.
(Optional) Select an option name in the Select Option dialog box, and click OK.
The new option name is displayed in the Option Name field.
Type the new value for the option, and click Modify.
(Optional) You can also add options to the network macro by choosing Select in the dialog box.
See Modifying DHCP Macros for more general information about modifying macros.
Select Notify DHCP Server of Change, and click OK.
This selection tells the DHCP server to reread the dhcptab table to put the change into effect immediately after you click OK.