add_filter( 'wpv_filter_query', 'func_change_filter_relation', 10, 3 );
function func_change_filter_relation( $query_args , $view_settings, $view_id ) {
    if ($view_id==1234) {
        if ( isset( $query_args['meta_query']['relation'] ) ) {
            $query_args['meta_query']['relation'] = "OR";
        }
    }
    return $query_args;
}