I called the CNO this morning, its 3 tries and that's it. There is no such thing as a refresher course and you get another try they said. Also, good luck getting a 4th try from the CNO, its almost impossible. Unless you had a hypoglycemic attack, or a heart attack, they wont give you another chance. They don't care about any other reasons unless they are medically relevant and you can also prove it with a doctor. The CNO is not on your side when you want a 4th attempt, they will give you %0 advice on how to go forward after you failed. They just don't care. My friend had to go through all this and even with medical proof, it was a long struggle for her because the CNO will do everything in their power not to give you that 4th attempt.