PO as err in VA41

D/ Friends,

In VA41, Iu2019ve configured PO as an incompletion log with warning indicator. So u201CEnter PO numberu201D is coming as a warning (message no. VU001). Iu2019ve also checked PO in VOV8 for the contract type. But I want to convert it into error message. How to do this?

Thanks.