Text reminders from appointment list

Hi ​@Fiona sopranoThis is likely due to the data tag you are using in your templates; it's most likely set to [patient_next_appointment], which will always highlight the patient’s next appointment rather than the 2nd and 3rd appointment example you’ve listed in your post. 

If you are sending SMS messages directly from the diary and a specific appointment, you need to create a new template and use the data tag [appointment_datetime], which pulls the data from the appointment in question. 

What I would suggest is using Dentally’s automated reminders, as this will save your staff time as they won’t have to send any manual messages to patients; the system can do this for you. 
https://help.dentally.com/en/articles/4219481-how-to-use-the-automation-settings

If you’re still struggling, then I’d suggest getting in touch with the support team via chat, as they’ll be able to look into your system directly.