In regards to a question posted earlier. No the assistant referee cannot overturn the decision of the head official of the match. There are there for a number of reasons, namely two sets of eyes on the situation. Sportsfans comment about agreeing with a poor call from the first official was unneccasary. Some times two referees will have a different opinion about a judgement situation. In this case the head official of the match ultimatly makes the decision. So that doesn't mean that he is agreeing with the call, he is just defaulting the call to the person who has to make it.