Permission has to be given to a user to cancel a PO, which is provided in SetupHub, User Management, Assign Users to ... Permissions.
The user and app (PurchaseHub) are selected, and:
- cancel all POs - the user can cancel any PO from All POs; and, or
- cancel my POs - the user can cancel any PO he or she 'touches' as a requester or approver from My POs page.
Once permission is given, select view in My POs or All POs. Details on the PO are then displayed. Scroll down the page & select Cancel.