How can I legally fire someone?

After Vivian invites Elle to a faux costume party (at which Elle is the only person to dress up) with the intent of humiliating her, Elle finds out that Warner does not think she can handle things either, so she decides to show him that she can. Things do not go as planned as Elle believed they would at Harvard Law. Many people are critical of her abilities, and few people take her seriously when she tries to act as a lawyer. However, she manages to find someone who believes in her, Emmett (Luke Wilson), a recent graduate and graduate-professor of Harvard Law. Eventually, she is able to become one of the top students in her class. One of her professors, Callahan, needs help on a case because his workload is just too much so he unusually takes on four first year students, one of them being Elle, they are assigned to the difficult case of a young woman, Brooke Windham, (a former member of Elle's sorority, Delta Nu and fitness instructor) who is accused of the murder of her older, wealthy husband. She discovers that the one witness who was being used by the prosecutors—the cabana boy, who claimed that he was having an affair with Brooke at the time—is actually gay (given that he is able to correctly identify her shoes as "last season Prada," something that a straight man should know nothing about), and who had been perjuring himself on the stand after being bribed by the real killer.