If you operate multiple clinics and need to stop sending reminders and follow-up messages for some of them, you can do this within your account settings.

First, head to Settings, and click on Business information:

Edit your chosen business, and under where it says "Enable appointment reminders and follow-up messages for this business", turn it to Off:

Hit the Update business button, and you're all set—now, reminders for appointments booked as well as follow-up messages at this location will not be sent.