Someone on here said that they did a conversion course and upgraded their first degree classification as a result. Is this possible "Find A" team?

It is not possible to upgrade the result of your first degree. However for the purpose of starting a PhD or some other professional postgraduate qualifications a Masters degree can improve the way people view your masters degree grade. For example most PhD studentships require a 2(i) or equivalent - a 2(ii) plus a relevant masters degree is considered as equivalent to a 2(i).