Suing the corporation. As stated previously, corporations are fictitious legal entities. They are ghosts, legal entities that exist solely because the state legislature has said they do. Like parents take care of their children, states take care of their corporations. So suing one is a little more technical.
Corporations only exist through their individual officers, agents, or employees.
Only a few of these can be served with suit papers to properly get the corporation in court. As a general rule, only those people who have a management-level job can be served with legal papers for the company. Usually it's a lawyer. The president or chief executive officer can also be served. Remember, everyone, including fictional legal persons, has a right to notice, and it is assumed that if even a minor corporate manager is served with legal papers, it is likely that he will contact the higher-ups in the company about it.