You can't with PDF::Reuse (AFAIK), but can with PDF::API2

In the Generic Methods, are the examples:

$pdf = PDF::API2->new();
...
print $pdf->stringify;

$pdf = PDF::API2->new();
...
$pdf->saveas("our/new.pdf");

$pdf = PDF::API2->new(-file => 'our/new.pdf');
...
$pdf->save;
[download]

You could maybe sprintf the above print and manipulate the scalar that way, but I would print it first to see what comes out, or maybe try openScalar

open($fh,'our/stream.pdf') or die "$@";
@pdf = <$fh>;
$pdf = PDF::API->openScalar(join('',@pdf));
...
$pdf->saveas('our/new.pdf');
[download]

You really only need to somehow grab the text with either of above, and then see what you can do with it.

HTH,
Gavin.