Closing Purchase orders - housekeeping

Currently it is not possible to close any POs unless the status is ‘Approved/Reserved’. This means that if PO has a status ‘Rejected’ the PO needs to be approved before it can be closed.  Whilst some POs need to be approved in order to close them, i.e. partially receipted and/or billed, others do not.  For example if a PO is rejected with no receipting or invoicing against it should be possible to close it without sending it back for approval.