Hii,
You can created the function below:
public static function changeEnvironmentVariable($key,$value)
{
    $path = base_path('.env');
    if(is_bool(env($key)))
    {
        $old = env($key)? 'true' : 'false';
    }
    if (file_exists($path)) {
        file_put_contents($path, str_replace(
            "$key=".$old, "$key=".$value, file_get_contents($path)
        ));
    }
}