If you need to cancel approval or disputing of an invoice, you can do so by recalling it, provided that it has not yet been exported to an accounting system.
To recall an invoice:
Select the (Invoice) icon at the top of the screen.
On the "Invoices pending processing" screen, select the "Processed" category.
From the list, select the invoice to recall.
On the invoice details screen, select Call back.
In the Callback invoice window, select Call back.
On the "Invoices pending processing screen", the invoice moves from the "Processed" category to "Pending".