When you want to Check-Out any guest you must have to go on Booking window of the guest. In that window you will find Check-Out option at the bottom- left corner of it. You just select Check-out option and then press the update button. The guest's status will be saved as check-out.
When you select the check-out option two operations will be generated as follows;
1. A message box will be appear to you to ask whether you want to give discount to the guest or not.
2. If the guest's payment amount is pending, another message box will appear to you to ask whether you want to check out the guest without accepting full payment or not.