Hi!
I was just in a similar situation in switching programs this year. You're going to have to make a choice in what you want for second year, business or sciences. If you know that you want to switch into business second year, then just register for all of the courses that you will need for your business program. During the year, you'll be asked to choose 4 level two programs you are interested in. As long as you make the cutoff and complete the pre requisites for your program you should be good to go! If you decide to stay in life sciences, than just choose your classes as a regular life sciences student. If you have anymore questions, let me know and good luck!