Step 1: Go to Calendar and find name of the appointment type you created for this event and click on it.

Step 2: On right navigate to date time and time of event. Click on "See Details", you will find the list of all the guests who have reserved this spot.

Step 3: Find "Download" button on guest list and click on it.

This will download an excel file of guest list with their name and email.

You can use this sheet for your marketing campaigns.