on the old server
run as administrator
C:\temp>netsh
netsh>dhcp server \\<old server>
netsh dhcp server>export c:\temp\dhcpdb all
copy “dhcpdb” to the new server
on the new server
C:\temp>netsh
netsh>dhcp server \\<new server>
netsh dhcp server>import c:\temp\dhcpdb all
Then restart dhcp service