With a significant schedule change, you're generally entitled either to request a different same-metal itinerary, closer to the originally booked schedule, that suits you better, or to have a full refund.

You are not automatically entitled to an upgrade or to be booked over to another airline.

If an airline ceases serving a destination for which you have a booked ticket, or if it cuts frequencies so your day of travel no longer has a flight, or if it subs out aircraft or service classes (replacing an F-equipped aircraft with an all-economy one, for example), those are all grounds for reasonable negotiation.