Change download file

in a form in the previous flow I put a file in the variable cam-variable-name = “file1” and in the next flow I can download it using cam-file-download = “file1” but in this form that I download I would like to change this file by another file but keeping the same name as variable file1. I can’t use a cam-variable-name because it will display a message that it already exists, any idea how to do this file exchange, of course without being there by the cockpit but in the form?