To change the status of a reservation, click on the status dropdown and select the desired status.
When one or more reservations change their status, an informative icon appears next to the trash icon, and a dialog appears at the top-right corner. The dialog allows triggering new notifications, according to the new statuses.
Either if you send the notifications or discard them (for instance if you are performing internal status edits), the informative icon of all the changed reservations will disappear.
Notification icon of a reservation status change
To re-send a confirmation email, just change the reservation status from confirmed to pending, and then change it back to confirmed. At this point, click "yes" in the notification triggering modal.