I'm just wondering if there is a way to re-read the preferences for a user without logging out and back in.In particular, I've removed a plist file for a user for printer preferences
Try running the command
sudo killall cfprefsd
from terminal. That will kill the preference daemon and it will restart, which should force to re-read the preferences files.
Thanks @Tribruin - did try that but it doesn't seem to do anything for the printing presets. Until I do the reboot or logout/logon but then again if I do that I don't have to