Suppose you start at Green and accumulate enough Club miles(30,000?, not sure) in the next 12 months and is promoted to Silver. Then, in the 13th month, ie 2nd year, your club miles balance is set to zero. In ur monthly statement, they tell u how many miles you must collect in the next 12 months to remain in Silver. If you collect much more, then you get promoted to the next level (ie Gold); if you just make, you remain in Silver; and if you don\'t collect enough, you get dropped to Green! This process happens every 12 months.