Right now this is done from a WOWAPPS level.
A simple email to firstname.lastname@example.org will turn this off and you will be set back to your normal delivery settings.
In saying that, in case of an emergency/urgent switch, you can still just turn off the delivery tab.
Please note, all delivery settings (except the Cash Option) will still be applied with 13cab delivery. So be sure to not have a minimum delivery fee set…