AFAIK, if you fail your PT test, the CFRC wants to see you've made an improvement to improve your physical fitness level before granting you a second attempt, which can be two weeks to a month away from the original.
If you fail your second attempt, more than likely you're going to have to really change your level of fitness before the CFRC will book you for a 3rd attempt. At this point you will have to prove to your CFRC what you've done and what you can acheive now.