Maybe it's a concept that I'm not understanding...
On page1.php, when the user enters an email address in the form and then clicks the submit button, this is saved into a session variable, right? On the next page, page2.php, that session variable is retrieved with:
$_SESSION['ReservationForm']['email'] = $_POST['email'];
This variable is displayed on the same page with:
<?php echo $_SESSION['ReservationForm']['email']; ?>
However, when the user clicks on the PayPal button and is brought to another page, and then clicks "continue shopping" and is brought back to page2.php the session variable does not display.
If I set the session variable on page2.php, it will display after being redirected from PayPal.