Did you apply to Ross and get denied in this cycle? If so, you cannot apply again as an undergrad. If you did not apply to Ross as a HS senior, you can apply at the end of your freshman year for a cross-campus transfer, but admission is far from guaranteed. You cannot rely on it. Ross admits 100 cross-campus transfers per year.
That said, you need to examine WHY you want to study business. Is it because you want a career in “business”? Or is it because you would love to take the courses that are required in a business school, that you love the area of study? If it’s the former, you do not need a business degree to have a career in business. It’s not like a career in medicine or law, where you MUST go to medical or law school to have those careers. I know LSA grads who work alongside Ross grads in the EXACT same jobs.