upload attached file cannot be deleted from form

Hi,

I must reset some fields on a form based on a drop-down box switch. The challenge that I face is that an upload file object that is among them is not reset. In other words, I cannot delete the file attached based on the drop-down box trigger.
Please note that upload file is not coming from upstream of the flow and I am trying to delete the file uploaded before the form is submitted

Maybe the upload file attached cannot be deleted the because the form is not submitted?
Thanks
John Balta