 <p>It works! Here is my completed code for adding an event and deleting one that occurs at the same time.</p> <pre><code>function createEvent(calendarId,title,startDt,endDt,desc) { var cal = CalendarApp.getCalendarById(calendarID); var start = new Date(startDt); var end = new Date(endDt); var event = cal.createEvent(title, start, end, { description : desc }); var events = cal.getEvents(start, end, { search: 'open' }); for (i in events){ events[i].deleteEvent(); } }; </code></pre>