How to modify the default message for automatic appointment reminders

Go to Setup and then Counselor/Staff

Find your name and go to the right to click the Add/Edit button under the Appt Email

At the top of the screen you have the option to select the template you want to modify - either the email template or SMS template

Next you have the option to set the number of days in advance the reminder should be sent

The next option to set is either Individual or Online.  Individual is for regular in person sessions.  Online is the option for telehealth sessions.