Customization on a Wordpress plugin

I'm using the plugin wordpress.org/plugins/participants-database/ on my Wordpress website to collect user data via an input form. This plugin, when a user insert a new record, checks if the email entered is already present in the database: if yes, it shows an error message. With an addon that I've installed (and it works) now the plugin checks at the same time, the Name and Surname fields. I want to customize it to check not only email address or name and surname, but 5 different fields.