How to change response of admin-ajax request?

WP_Fullcalendar::ajax overrided by WP_EventsManager plugin in file em-wpfc.php, if wpfc and wpem used in combination.

Here is my final code in functions.php

/**
 * Translate WP_Fullcalendar titles for events
 * @param $items
 * @return array
 */
function wp_fc_translate($items)
{
    foreach ($items as &$item) {
        $item['title'] = apply_filters('the_title', $item['title']);
    }
    return $items;
}
add_action('wpfc_events', 'wp_fc_translate');