I want to update purchase agreement data in my tables. But can't

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Dear ,

I want to update some data in my tables . i want to update purchase agreement in which i tried to update data through FBDI (import blanket purchase agreement) but its not updated also its creates a new data in table which one i update in through fbdi.

Please guide how to update it. kindly see attached picture also i want to updated (Group requisitions , Group requisitions lines.)

and it is lie in PO_headers_interface table.

Thanks