function em_mod_ticket_booking($price, $EM_Ticket){
 if( is_user_logged_in() ) {
	if ( is_array($EM_Ticket->ticket_members_roles) ){ 
		$user = wp_get_current_user();
		$roles = ( array ) $user->roles;
		foreach($roles as $role){
			if ( $role == 'administrator' && in_array( $role, $EM_Ticket->ticket_members_roles ) ){
				$price = $price - ($price * .7);
			}
		}
	}
 }
 return $price;
}
add_filter('em_ticket_get_price','em_mod_ticket_booking',100,2);