The registrant will need to have their User Id and Password in order to update their registration. 

To obtain  their User Id and Password:

1. Go to http://www.doubleknot.com
2. Click on Client Logon in the upper left of the screen
3. Select If have forgotten your User ID or Password click here link.
4. Enter the recipient's email address and click the Send Password button.  The system will email the User Id and Password to the address entered.

To modify the registration:

1. Go to http://www.doubleknot.com .
2. Login using the User Id and Password from the email.
3. Select the View Registrations link.  This will display a list of all events for which the user is registered. Note depending on your profile you may need to first click on My Information before seeing View Registrations. 
4. Select View Details link for the event.
5. Assuming they are allowed to edit their event, there will be an Update button at the bottom of the page.  If a payment is due there will also be a payment button.