sample.php

<?php
class Foo
{
    protected $name = '';

    public function __construct($name)
    {
        $this->name = $name;
    }

    public function getName()
    {
        return $this->name;
    }
}

class Foo2 extends Foo
{
    public function getName($addedParameter)
    {
        return parent::getName() . $addedParameter;
    }
}


$foo = new Foo('Mike');
var_dump($foo->getName());

$foo = new Foo2('Mike');
var_dump($foo->getName('!!'));