How to navigate from Fiori to SAP GUI instead of Fiori to Fiori

Hi,

I am using the Fiori app "Manage Purchase Requisitions". When I select a Purchase Requisition and click on the button "Create Purchase Order" the app open PurchaseOrderPreview from where a Purchase Order can be created. But we need is to navigate directly to the ME21N WebGUI app when we click on the button and NOT to the default Fiori app.
How this can be achieved?

Many thanks!