You can access your event's website and see it as what a specific participant would see (this depends on what stage the participant is currently in). By doing so you are also able to take any action on any form that is accessible by this participant (i.e. updating any field in these forms).
At Event level, go to the Participants module and click on the participant of your choice. Then click on the Stage tab, and click the "Impersonate" link. This will redirect you to your event's website.
