A reservation can only be canceled if there's no payment on the folio and if all the folios are still reservedthe status of the guest folio is (Reserved, tentative, or Quotation) or if the room has been canceled because, in Ehors, the room can be canceled individually without having to cancel the whole reservation.
How to cancel a reservation?
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Tick the "canceled" status and then click search. This will show you all the canceled reservation
This is how it looks like after clicking search.