How to Restrict/Remove submitted PO from Create Invoice window in Supplier Portal

Summary: Supplier has submitted PO (PO No: 12345) for invoice from create invoice page from supplier portal, but if again supplier wants to submit PO for invoice the same PO no: 12345 is appearing in the identifying PO field which is already submitted.

How can we restrict/remove already submitted PO from create invoice page of supplier portal.

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