<p>I guess it depends on what you mean by "event is changed in the Event Calendar." Note that an event is not a calendar, they just show up on the calendar. Event Registrations themselves have various email notifications. The user can be emailed when they register (like a receipt) which can give them more details about the event than you put in the description they saw online. Events can also send "reminder" emails on a date you choose prior to the start of the event. Think of an event that's been open for registration for a couple months and you want to send a reminder about it the week before it starts... again this can contain additional info, etc. Finally, there are Event Payment reminders that can be sent (manually or automatically) for events with payment and the user still owes part of the amount.</p><p>Beyond that, you would be emailing registrants manually from either the Registrants (the people who are attending the event) grid, or from the assciated group (if there is one) the registrants are placed in... usually you have an event associated with a group when you need check-in for it, as check-in happens via a group, not an event. There is also a "group placement" function that lets you manually put registrants into groups... think Youth camp and cabin assignments (groups) or similar. The gist here is that you are emailing details/changes/info about the event just by using the registrants and/org associated groups grid(s). Rock doesn't "automatically" notify people about "changes" because it doesn't know what those changes are ;-) It takes a human to communicate these things.</p><p>If you haven't already, I suggest you read this guide&nbsp;<a href="http://www.rockrms.com/Rock/Book/29/78">http://www.rockrms.com/Rock/Book/29/78</a>&nbsp;It explains how events work much better than I have!</p>