If a participant contacts you to make changes to their registration, then as the event organiser you have the ability to update their details in the system (more than the participant has to edit on their own).

First you need to find the participant. You can do this via the Participant Search function (Admin Menu - left hand side of your screen) or from the Manage button on a specific form and then click People. 

Once you have found the participant you need to edit, click on the Select button. This will bring up their Participant Summary page.

From here you can edit the following sections:

Group / Team Details - You can have the person join / leave / change teams

Personal Details - You can click on EDIT and update their personal details (i.e. Name, DOB, contact details etc). Just click save at the bottom of the page when you are done.

Event Pack - You can EDIT their Event Pack selection

Categories - You can EDIT the Participant's Event / Sub / Award Category selections. If you click on Edit, be aware that this will then force you through the rest of the registration flow because their may be new unanswered questions or new dependant add ons that were not availble to the Old Category selection.

Event Questions - You can EDIT the participant's answers to any Participant Questions.

Financial Summary - You can add additional Merchandise / Add Ons or edit any purchases Merchandise / Included Items. You can also remove any Unpaid charges from the financial summary at this point. And of course you can process payment from this point (which could be either a normal payment or an offline payment)

Notes - You can also add notes to the participants record (these are not visible to the participant).

Change Event - You can move the Participant from one registration form to another.

Withdraw From Event - This updates the Participant's status to Withdrawn and essentially removes them from being registered in the event. Note: This does NOT refund the participant in any way. To refund a participant see the useful links section below.