Interesting question. So say I'm a B1 with daily experience as B1 and a few type ratings. I did the theoretical exams for B2 in a PART147 5 years ago, but no practical experience as B2 the last 5 years and no type ratings as B2. Do I have to do the B2 theoretical exams again if I want to become one? Or just the practical exams for B2 which I never did?