If you want to stop only one day for your watering schedules, you can create a restriction (Settings->Restrictions) or set your device in paused mode. (Settings->Controller->Enabled)
If you want to stop watering for smart watering and create your own programs, please go to Settings->Zones->Smart Zone and toggle the enable button. When the smart zone is disabled, the system will strictly follow the user program to water the zones.
Please let us know if you have any further questions.