It all depends on how ur terms are with the owner. Usually, u need to give him an advance notice of 30days stating that u would be leaving in middle of the period mentioned in the contract. There were insidence, where the owner asked for 2 months payment, cos of not giving any noticed period by the occupant. In which case, the occupant would be lossing out on a lot of money. So, get in touch with ur owner and talk to him about ur intentions, he can certainly out sum light on the topic.