You could use an “After Create” event handler for your request entity in the domain model. In your new “ACR_Request” microflow, you could retrieve the respective person and connect it to your request by setting the association accordingly.
Here’s a guide to event handlers: https://docs.mendix.com/refguide/event-handlers
You could fill this value on creation of the record that is on the page. In the MF that opens this page, do a retrieve and a count to see if only one value is there. If there is 1 value, change the newly created object to that value, else, leave it empty.
Or just retrieve the $currentUser and add that to the newly created object, if that is the case.