Hi,
You may use the ME2N transaction with selection parameter as WE101 which will give you open PO's. Please note that the report will give you PO's which are open, irrespective of whether partial GR is posted or not. You may use selection parameter WE102 also, which will give all PO's with a GR.
If you want only the PO's for which partial receipt is posted, you may go to OLME - Reporting - Maintain Purchasing Lists - Selection Parameters - Define Selection Parameters, and copy WE101 and create new as below:
Use the selection parameter in ME2N and test the scenario again.
Regards,
AKPT