Possibilities for participants to edit their registration

How can participants edit their registration?

This is usually not enabled, as the registration should be binding for the participant and deselecting or changing registration options may alter the fees or these participants and can cause extra work for the organizers. Therefore, it is usually advisable to change registrations for participants only on request and only by the administrators / organizers of the event.

You can find more information here:
http://www.conftool.net/ctforum/index.php/topic,214.0.html