Get a new LOA for a new program to the school on your study permit for at least a semester. Then change schools if you want. Posting under Quebec Immigration so assume the school on your permit is in Quebec.
I have gotten a new letter of acceptance from my new school , no is not in Quebec
New letter for another school is not relevant. You cannot change schools unless you have studied at the school on your current permit. You must attend the school on your permit for at least a semester, and then change. If you have no plans to go to the school on your permit, to attend the new school, apply for a new study permit. The link provided is very clear.
