m77nf

I’ve found another code myself.
Anyway, thank you very much for your help.

<?php

add_filter(
    'init',
    create_function(
        '$a',
        'global $wp_rewrite;
        $wp_rewrite->author_base = "the name";
        $wp_rewrite->flush_rules();'
    )
);
// Put Your ideal slug instead of "the name"

?>