Error canceling Purchase Order

We have the following case, when trying to cancel a Purchase Order of the Requisition this has already been received by a user who is currently on operational leave, the Requisition was reassigned so that another user can cancel it and thus cancel the Purchase Order but it is not appearing in the Purchase Order tray to undo the reception and thus cancel it.

When trying to cancel the requisition, the following message appears:

You can't cancel this record because invoiced or delivered distributions exist.

When filtering the PO to undo receipt it does not appear in the search:

Please, your help.