After reading the advice in this forum, I attempted to expand a range.

I exported the subnet using the DNS/DHCP Management Console.
Then edited the exported file, changing only the ending address of the
range.
Deleted the subnet in DNS/DHCP Management Console.
Deleted the subnet in NWADMN32

When I attempt to import the modified file, DNS/DHCP Management Console
never finishes.
It displays:
-----
The import program is updating the database. Please wait while the
transaction occurs.
Transferring IP address configuration to NDS.
-----
NW51SP6
NDS 7.61
dhcpsrvr.nlm 3.12f
management console recently reinstalled from dnsdhcp3.exe

advice please?
.....Gregg Nicholas