It's best to cancel your membership right at the gym and have them give you a letter stating your membership has been cancelled. They can do this for you on the spot. Tell 'em you're leaving HK. They can't really persuade you to stay on as a member if you're not even going to be here.
When I was offered personal training, I was perfectly honest with them. I simply can't afford it. They had no choice but to accept that. Once my year was up, I took my money over to Season's.
I was a member of Cali Fitness in LKF back in 96 or 97 (before it was even open). It was a much better gym then, and their business practices were better too.