Thanks for your reply.here are the situation:-
user OAR will be enter PO then print PO and later approval process with sales order entry proc.option blank the awaiting approval process status code.I have duplicate and it never update F4209 therefore not able to view in approval review and cannot be approved.
You may try this out in your test environment.
Not sure what is causing your problem. First thing that springs to mind is that the order is going to the approval status as a result of the order activity rules and not as a result of approval rules as the F4209 is not updated. It may be worth having a look at the activity rules to see if this is the case.