Remote PHP script to rename files

I need a Simple php script written to rename a file in \'x\' directory and relocate the same to new directory \'y\'. The complicated part is that this script will be remote launched alongwith a survey that gets completed using limesurvey and some values have to be picked from the completed survey when the submit button is hit. If you are familiar with Limesurvey, attached here is how this is supposed to work. If you are not familiar it may be a bit complicated but you can try: See Attachment. Budget is fixed at $30