KACE Product Support

When I had this issue last time I did the following:
1. update all settings in the appliance
2. making a DNS A record from the old to the new appliance name
3. created a CIR ShellCommandTextReturn(cmd /c more c:\programdata\quest\kace\amp.conf|findstr host) OR ShellCommandTextReturn(cat /var/quest/kace/amp.conf|grep host)
    I use Windows and Linux in my env so I needed to collect both
4. I created a Smart Label which contained all systems with the old host entry (the wizard is sweet for that) The result is something like that (change the ID to the right inventory item and the host string correctly)
SELECT MACHINE.NAME AS SYSTEM_NAME, SYSTEM_DESCRIPTION, MACHINE.IP, MACHINE.MAC, MACHINE.ID as TOPIC_ID FROM MACHINE   WHERE (((not exists  (select 1 from MACHINE_CUSTOM_INVENTORY where MACHINE.ID = MACHINE_CUSTOM_INVENTORY.ID and MACHINE_CUSTOM_INVENTORY.SOFTWARE_ID = ENTERTHECORRECTIDHERE and MACHINE_CUSTOM_INVENTORY.STR_FIELD_VALUE not  like '%ENTERTHENEWDNSHERE%')) ))  
5. I created a report for the host entry
6. I created a script Launch “$(KACE_APP_DIR)\AMPTools” with params “-resetconf host=NEWDNSHERE” The script ran once a day and on the next check in.

All systems went into the smart label during the next checkin and ran then the script soon. This allowed them to checkin into the box with the new DNS name without any interruption and the went out of the smart label.
As soon all machines were updated, the A-record was removed.
If you have multiple licenses you can also run both appliances at the same time and see how the agents pop up in the new appliance.