If there were date fields on a form, then that would create potential for triggers based off that date field. So it's not an appointment but it could work in a similar way.For example: Gym membership hold request. The member requests a hold from [start date] to [end date].This triggers a 'send before' style campaign where 7 days before they're due to restart they get a reminder and then 2 days before they're due to come back they get another SMS and then on the day they're due back another.