Can participants edit their registrations?

Are participants able to change their registration for participation?

This is usually not enabled, as the registration should be binding for the participant. Deselecting or changing registration options may alter the fees of these participants. Furthermore, as an organizer you want to stay informed about the booked items. Therefore, it is usually advisable that only administrators/organizers of the event change registrations for participants upon request.

You can find more information here:
Allow participants to edit their bookings in the registration for participation