how can a common man play a role in reforming the political parties

The common man has responsibility to take an active role in government. That means that he must take note of the political parties, their beliefs, and their actions which support those beliefs. He can participate in the party by challenging their ways of acting, working for the positive improvement of the party, acting as a leader or some kind of "chair" on a particular issue, or just generally be "there" when the country needs the kind of help the common man can offer.