BG is right. You should know the reason why you got rejected first. The chance of having school to change its decision from spring turn to fall to the same applicant is bad. You should try to re-write your assays, and to show the improvement of your application package. This is the only way to convince school to change their decision.
However, there is no problem for applying different majors, as each department has its own system. I’d assume the rejection might be the assays you wrote. You should have someone to help to improve. Let me know if you need assistance.
judiewu@umich.edu
Jwu