Changing Buyer using Page Composer in Purchase Requisition

Summary:

Hi,

I'm trying to change the default Buyer using Page Composer after submitting the Requisition. I want to set the Buyer based on the Requisition Amount submitted. I've set all the condition, however, the Buyer information haven't change even though I change the Buyer display value.

May I know if there are any ways to solve this problem through the Page Composer, or any other ways without using the Page Composer? I attached below the screenshot of the problem I'm facing right now.

Thanks.