How to block change order creation for approved PO's

Summary:

How to block change order creation for approved PO's

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Hi,

I would like to block change order creation possibility, is there any privilege I can get rid of ? I saw there is a privilege named "Change Purchase Order" on Buyer Role, but it seems I can't delete it unless I delete the whole role "Purchase Order Authoring Custom". But if I do this, I can't create orders anymore.

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Oracle Cloud

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