You may have been testing prior to your event, or your event may be a multi-day event that allows for the same tickets to be presented for the following day/session. Check-Out All Tickets allow you to Check-Out tickets on mass, so that they can be presented once more for successful Check-In.
You will have the option to Check-Out by Event or Ticket Type.
When actioned the tickets that had the status of Checked-In be updated to the status of Checked-Out.
To Check-Out All tickets:
On the navigation menu bar, select Settings
Select Check-Out Tickets
By default the events selected for scanning will be selected.
If you wish to Check-Out ALL tickets on the event/s selected, tap Check Out Tickets
If you wish to only Check-Out all for a specific ticket type/s:
Tap Ticket Types
Select the ticket type/s you wish to Check-Out, and then tap Check Out Tickets
If you have a large ticket volume, it may take a couple of minutes to complete.