You can absolutely add multiple email & SMS reminders which can be set up to be sent on different times. You start by going to the “Set Up” tab and click on “Emails & Text Messages” and choose on "Reminders":

Since you already have an existing Booking Reminder set up on your account, you can then click on "Add Another Template" :

Where you can set the time of when you want this booking reminder to be sent and the content of the booking reminder email:

Hit “Save Template” to save the changes you made.

You are also able to set up multiple email and sms reminders based on the booked service. Upon clicking on the "add template" button, the system should allow you to choose which services are assigned to the 2nd template and which services that are booked can receive the specified reminder:
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