replacing mysql $link supplied data, a question?

[XSLTel]

no Lock Down I didn't meant that but thanks for reply

below example can make my request clearer :

$mysql_user = "root";
$mysql_pass = "rootpassword" 

now after it gets executed

$link = mysql_connect('localhost', $mysql_user, $mysql_pass); 

by default the code will resulted in this

$link = mysql_connect('localhost', 'root', 'rootpassword'); 

I want to change the above resulted code with another username (root) only username without touching the variables mentioned above