Control when reminders fire
To control when customers receive their SMS or email reminders for upcoming appointments, click Settings > General Setup Scroll nearly to the bottom to Class & Appointment Reminders.
Note that if reminder emails and / or SMS (appointment only) are turned off, these reminders won't be sent.
Disable a reminder
Email or SMS reminders can be disabled from Studio Setup > Transactional templates > select SMS or Email > choose which reminder to disable > select Disable