Change Message when using Manual Booking

<?php

add_filter('em_action_booking_add', 'em_action_add_booking',  100, 2  );
function em_action_add_booking( $feedback, $EM_Booking ){
 $add_txt = '<a href="'.em_wp_get_referer().'"">'.__('Add another bookingx','em-pro').'</a>';
 $feedback["message"] = esc_html__emp('Booking Successfulx') .'<br><br>'. $add_txt;
 return $feedback;
}