You can send a link to registered participants so they can modify their registration information. This can be useful if you want to allow participants to modify their previously entered information, or to answer new questions you have added to the registration form since they've registered. 

  1. Go to 
  2. Click My Events
  3. Click the name of the event under the I organize section
  4. Hover your mouse over the Participants tab located on the purple bar
  5. Click Edit Emails
  6. Create a new message template using the New message link on the top left of the page. 
  7. In the body of the email, click the green + icon
  8.  Choose Link to Update Registration

You can send that email to Confirmed participants or manually select recipients from your participants list by checking the box left of their name on the Participants tab and clicking the Emails button at the top.