DHCP to static without reboot?

[Mark Pavlichuk <pav5088@internode.on.net>]

I can't seem to change the configuration of a nic from DHCP to static in 
Stretch (without rebooting) - I do this a lot so I don't want to have to 
reboot every time.  I'm using the old "killall dhclient;ifdown eth0;ifup 
eth0" method which also still seems to be in the documentation... at 
least on the debian.org site.  I've also tried doing various 
combinations of "service stop/start/restart networking" along with 
ifup/ifdown commands to no avail.  Is there some special new magic?

--
Mark Pavlichuk