There are settings under Patient Chart:  Patient Info -> Demographics ->  User Defined Fields. You have the three options you can set to "No" when you click in the cell to the right of the setting name. Just be sure to enter the date in the setting field directly under which will be when this change takes place.

For example Receive Email Appointment Reminders = "No" and Email Reminder Setting Date = "9/24/2020"

Be sure to remember to click on Save at the bottom of the screen to save the settings. Also remember that SMS = Text messages.