12 Month Internship With Final Year of BTM Program Left

I secured a 12 month internship offer starting in fall and am going to be leaving co-op as it didn't really help. I was wondering what I would need to do in terms of moving my last 2 semesters of BTM for later. Can I still remain full time, would I need to fill any forms, is there any requirement where I must indicate that I wont be attending????