How to convert an XML file to a BOW file?

For this, you must download a validation module, which can be done via this link:

It converts XML to BOW and also does checks.

Also see:

Is it possible to reset the sheets with status "sent" to change and create a new file?

Yes, by deleting the shipment via Menu: Belcotax - Shipments

This is only allowed if the BOW has not yet been submitted