Look into code at EVNTREG.php file, just from line #251:
/********************************* ADMIN MENUE ********************************/
//
#function to load plugin admin menu to Admin sidebar
function evr_admin_menu(){
global $evr_date_format, $evr_ver;
$version = "EVNTRG_" . $evr_ver;
$role = 'manage_options';
#Create Admin Menus
add_menu_page($version, $version, $role, __file__, 'evr_splash');
add_submenu_page(__file__, 'Configure Plugin', __('Configure','evr_language'), $role, 'configure','evr_admin_company');
add_submenu_page(__file__, 'Categories', __('Categories','evr_language'),$role, 'categories','evr_admin_categories');
add_submenu_page(__file__, 'Manage Events', __('Events','evr_language'), $role, 'events','evr_admin_events');
add_submenu_page(__file__, 'Questions', __('Questions','evr_language'), $role, 'questions','evr_admin_questions');
add_submenu_page(__file__, 'Manage Attendees', __('Attendees','evr_language'), $role, 'attendee','evr_attendee_admin');
add_submenu_page(__file__, 'Manage Payments', __('Payments','evr_language'), $role, 'payments','evr_admin_payments');
add_submenu_page(__file__, 'Register Plugin', __('Register Plugin','evr_language'), $role, 'evr_register','evr_registration');
if (get_option('evr_was_upgraded')== "Y") {add_submenu_page(__file__, 'Remove Old Data', __('Remove Old Data','evr_language'), $role, 'purge','evr_clean_old_db');}
add_submenu_page(__file__, 'UnInstall Plugin', __('Uninstall','evr_language'), $role, 'uninstall','evr_remove_db_menu');
}
/********************************* END ADMIN MENU ********************************/
At line #257 plugin defines, which role it uses to setup menu permissions for its users. You may change ‘manage_options’ to ‘editor’ if you wish to permit your editor to manage this plugin with full access.
You should trust enough to your editor or check, if you don’t make some security whole at your WordPress setup with this change.