Admit a waitlisted attendee

• Event → Registration→Waitlist
• Select the attendee(s) you'd like to move off of the waitlist by checking the box in front of their name
• Choose Attendee Status→ Confirmed→ Update 

This will switch the attendees into a Confirmed / Active status. It does not automatically email them or charge payment. You will want to do that to let them know they have been accepted into the event and payment will be processed.