Updating Delivery Address in PO

Hi guys,

I have successfully created PO using BAPI_PO_CREATE1.

After creation of PO, in the same program, I am trying to use BDC to insert data into the field ADRN2 ( under delivery address tab in ME22n ), but I keep getting error message saying that <PO number> is locked by myself.

Any idea how I can pass along the ADRN2 during PO creation? or any idea how can I 'unlock' the PO so that I can proceed with the BDC data insertion?

Thanks!