How to issue credits in bulk

First, put all registrations in a canceled status: 

1. Event → Registrations → Attendees
2. Check the box to the left of the Choose Attendee Status box to select all of the registrations
3. Select Cancelled from the Choose Attendee Status drop-down list
4. Click the Update button

Next, use the Refunds & Credit tool to credit everyone: 

1. Events → Registrations → Refunds & Credits
2. By default, all of the attendees in a canceled status will be in your list and the full amount they paid will appear in the credit box.
3. If you do not want to provide a full credit, adjust the amounts in the credit box for each attendee accordingly.
4. In the Options box under the list of attendees decide what kind of credit you want to offer by changing these options:
   1. Restrict to a certain event or use it toward all events
   2. Restrict to a certain type of event
   3. Create an expiration date for the credit
5. Select Preview Credits 

A brief note about why the credit is being given will help in remembering later. You may also consider adding the name of the person who processed it. Now you can review the pending credits and choose to send an email to everyone receiving a credit. After completing this step, select Save Credits Now and the credits will be applied to each attendees account. 

The next time the attendee registers for an event with your organization where the credit can be used, it will appear on their payment screen to be applied towards their balance.