Hi!  I don't think is possible otherwise everybody would be doing that.  It would be nice to be able to do that but I think it would be hard, at the same time,  because if a class requires you to take a class before that one, it would be because the prerequisite class will prepare you for the upper class that requires it.  So, when you walk in that upper class, the instructor will assume that you already have learned certain skill that you need in order to keep up with the class and not fail it.