Re-send a booking confirmation email.

Step One.
Navigate to the booking of the email you want to re-send. Click the eyeball icon to view the booking.
Assure that the email address in the booking is correct.

Step Two.
In the top right of the booking, click "Comms."

Step Three.
In the row "Booking Confirmation" click "Email" at the very end. 
A prompt will pop up asking you if you are sure you want to send the email. Click "Send."