Your instructor may recommend or even require that you retake a exam or participate in an additional pool training session before moving foreward(additional fees will apply). Many of us don’t take this kind of news well and the decision may interfere with your vacation plans. It may also save your life. Your instructor must adhere to a set of standards set by the Professional Association of Diving Instructors(PADI) and the RSTC. He or she has years of experience and training assessing would be graduates. Trust your instructor’s decision.