A couple people reapply to first year in Canada after one year of school here in Ireland.
As for transfering, I know of a couple people who after their third year, applied to American schools to transfer. So they did their 4th year (out of 5)here and then went back into 3rd year in America. Med school takes 1 extra year if you do that but that's really the only way you can transfer. Never heard of anyone transfering into a Canadian school.