What if I am notified beforehand about the change in schedule

If there are some changes to your flight schedule, you should be notified not less than 14 days before the departure. And if you do get notified in advance, you get the chance to book the alternative flight. Note that the changes may be made only to the time and date of your flight, not the flight number. Otherwise, you can claim for flight cancellation refund.

In case you are notified about the changes to the flight schedule less than 2 weeks before the departure date, you can claim compensation by way of alternative flight or a full refund for the flight that was basically cancelled.

Different airlines offer different conditions under which you may ask for compensation but the Regulation EC 261 is one and the same instrument you are supported by.