Select Registrations from your main menu.
Search for your registrant and click on the pencil to edit.
Make your changes and save.
If you make a change that results in a charge, you'll have the options to not charge, charge the card on file, or add a new card to charge.
If you make a change that results in a refund, you'll have the options to not refund or refund the card on file.
If you'd like to resend the confirmation email with a custom note, you can select this option.
Once saved, it will resend the confirmation with your note at the top: