CA Top Secret how to remove a CPF NODE from the NDT table?
If you don't plan on bringing that system back up, you should deactivate the connection to that system on the other systems.
TSS REM(*CPFRECV) CPFNODE(node) and then do a TSS MODIFY(CPF(REFRESH))
This is if you do not want command to go to the system taken off-line
because once REMOVED they are gone.