Running CRON jobs on a Mac

Finding this helpful:

http://www.alvinpoh.com/how-to-add-cron-or-cron-like-jobs-to-mac-with-mamp-or-otherwise/

however, I am confused. You launch the job cycle like this:
sudo launchctl load /Library/LaunchDaemons/yourfile.cron.plist

But how do you UN-launch it, say, to restart?