situational irony is when something is expected to happen but the something else occurs. In this case it is Romeo try to win over Rosaline, but then falls for Juliet.
Answer: Calpurnia basically explains that she would not like to appear as though she is "puttin' on a show", so she changes her speech to blend into her surroundings. She then tells Scout that you can't change individuals or show them except if they need to change.
