You don't need to cancel your registration. If you don't need to buy this cellphone, just don't click the 'Buy Now' button. Registering for sale does not make you liable to purchase.
Even if you click the 'Buy Now' button and the Redmi 1S is added to your cart, you can still go ahead and cancel your purchase by not paying for it in the given time period. Your cart will automatically be emptied of this device.
That being said, I would suggest you to ask your friends if they'd be interested in buying this cellphone. Since this device is still high on demand, it would give them a better chance of getting this cellphone if you also use your registration for them.