How to Contact Event Registrants in Communications Center To contact all event registrants through Communications Center, follow these steps: Create a new message. When you’re ready to send it, click Add Recipients. A list of recipient options is displayed. Click From the Address List of Events and Donations. In the Organization menu, select the organization that contains the event. By default, the message will be sent to all registrants and registration owners. To limit the message to registration owners, select Only registration owners. Click Include. Complete and send the message as usual. Related articles IMPORTANT: Handling Refunds Greater than $5000/Day Why is there a Doubleknot charge on my credit card? Who's Doubleknot?