change nickname

[blitz]

hi all
i have the phpfreechat into an iframe i send to it the username with $_GET but if i change the username (with the login) the chat don't show the changes

example:

$username=$_GET['name'];

if ($username =='') {
$username="guest";
}

$params = array(
...
...
"nick" => iconv("ISO-8859-1","UTF-8",$username),
...
...);

then at the first connection my nickname is guest if now i log in for example as admin ($_GET['name']=admin) the chat don't change my nickname.

i think that could be with the session destroy function or something like that.

someone can help me?
thanks in advance