You can quickly send an email to all the people in a specific class. Simply go to the class detail page, and underneath the button to mark attendance is a blue button to send an email.
This works exactly the same as email in other parts of Punchpass - click to button to show the form, fill out the subject line and message, and click send. Done! Every attendee and reservation will receive an individual email.
This allows you to quickly reach all the people who have reserved spots in a class (for example - if you need to cancel it.)