In fact, why do you want to transfer the card? Did you sell the card to others, and then others registered their information? Actually, it's not that much trouble I also know the rules of the gym. All you have to do is go to the front desk of the gym and tell someone to change their phone number. In fact, to be honest, people don't know you at all, unless you often book a gym with a personal trainer. So just change your phone number, and just give me a number when you can go next time.