php using regx to replace domain

use regx replace ‘
https://www.clrs.me/abc/index’
to ‘
https://www.muker.club/abc/index’

$a = preg_replace('/(https):\/\/([^\/]+)/i', 'https://www.muker.club','https://www.clrs.me/abc/index');

echo $a;

result is
https://www.muker.club/abc/index