Edit a PHP script

edit a PHP script to add a new function with out affecting the existing function (send e*mail via STMP server to e*mail address). [ details below ] 1. [ System Workflow Overview ] The system is a p*ayment gateway which processes credit card p*ayment which then redirect to user URL with transaction information included [ Return URL Code Sample In attachment ] 2. In my web server directory is a folder called return which has an [login to view URL] file which below reads the transaction return URL information then redirects the user to a success or fail page. I need you to add an additional function to the index file so that base on page the index file redirects user to based on URL data the PHP script will send to two e*mail (one specified the other it's the e*mail data in the URL info)