How can I easily change my time-zone in Arch/Xfce?

Since I move around, I need to be to change time-zones frequently. I'm on Arch/Xfce. How can I do that? I've tried right click on the watch on the top panel -> properties -> time settings -> time zone. It didn't work. When I type a time-zone, it's not auto-completing and not showing suggestions. When I enter it, nonetheless and press Ok, the time doesn't change according to a new time-zone. What's the proper way to do that?