Question: A Certified Nursing Assistant (C.N.A.) who is practicing under the supervision of an R.N./L.P.N., even if the supervising person is not present so long as the R.N./L.P.N., left written instructions. a physician has determined that the C.N.A., has sufficient experience. the patient approves. the R.N./L.P.N., can be easily contacted for consultation or advice.