EU rules allow this with at least 14 days notice. Less than that, and the airline needs to provide compensation — €250, €400 or €600 depending on the length of the flight.
https://europa.eu/youreurope/citizens/travel/passenger-right...
https://europa.eu/youreurope/citizens/travel/passenger-right...
Also in my experience airlines will go out of there way to help and rebook. Sometimes it is the next day though which sucks but isn't totally apples to oranges ;)