[web] [PHP] Pass $_REQUEST through header('location:...')?

I have one page that takes some user input. Its form submits to itself. The page processes the input. If the input was invalid, it displays error message(s) and the original form. If the input was valid, it does some processing and then does a header('location: ...') to go on to the next step. The problem is, the second page needs the content of the HTTP request ($_REQUEST) from the first page, and I'd like to not pass the information through a querystring in the URL (the information is somewhat sensitive). Is there a clean way to simply pass the $_REQUEST on to the next page?