Is there a method to convert an instance of an object to another class?

e.g.

PHP Code:
class SimpleObject {}
class 
AdvancedObject {

    public function 
AdvancedMethod()
    {

    }

}

$object1 = new SimpleObject();

// cast
$object1 = (AdvancedObject$object1;

echo 
$object1->AdvancedMethod();