A PO can be cancelled even after it has been confirmed and dispatched to the vendor. You can't cancel a PO if the order or some orders attached to the PO have the status of part filled or filled.

To cancel a PO or POs:

1. Add the POs to the Purchase Order List, and select them.
2. Click Cancel.
3. Click Yes at the confirmation prompt.
4. You'll then be prompted whether to send a cancellation notice to the vendor. Select a reason for the cancellation, select the delivery method for the vendor or vendors, add a note if you wish and then click OK to send the notice. Or simply click Cancel if you don't want to send a notice.