Hey! Congrats on the acceptance.
If I were you, I would call the office of the registrar, and they'll direct you as such.
Telephone & Fax
Telephone: 905.525.4600 Fax: 905.527.1105
Office Hours
Monday, Wednesday, Thursday, Friday 9:00 a.m. - 4:00 p.m. Tuesday: 10:00 a.m. - 4:00 p.m.
But I do know that to switch programs you need a pretty good average, and sometimes it's harder to get into programs because kids coming in from high school get prior advantage. (I've heard that for some programs, like Kin).
Good luck!