The "finally" block can change the exception that has been throw by the catch block.

<?php
try{
        try {
                throw new \Exception("Hello");
        } catch(\Exception $e) {
                echo $e->getMessage()." catch in\n";
                throw $e;
        } finally {
                echo $e->getMessage()." finally \n";
                throw new \Exception("Bye");
        }
} catch (\Exception $e) {
        echo $e->getMessage()." catch out\n";
}
?>

The output is:

Hello catch in
Hello finally 
Bye catch out