Fixing a bug for a calendar software widget

A calendar export feed (ICS/ICAL) from a particular company is mistakenly adding an extra day to each calendar event. I need a temporary fix to this bug until the company fixes their own mistake. Here are the details: 1. Identify the offending calendar feeds 2. Add extra day to each calendar entry under DTEND so that the calendar widget displays it correctly. So the code should go something like this: IF prodid EQUALS companyxyz OR companyabc THEN for each entry add one day to DTEND Since this is a temporary fix, the code needs to function on it's own be well identified in the PHP script and be commented out/deleted when it is no longer needed.