Originally Posted by DeathSlam

Welcome to Flyertalk, sadly many join under these sort of trying circumstance.

Finnair will automatically offer you replacement flights if your flight is impacted.
You will be able to accept these in the app on your phone. If the flights are acceptable, that's all you need to do.
You will have been sent a link to "your rights" which outlines what they will do for you in the event of problems. It's worth a read, it's quite short and clear. Part of that is a hotel night if needed.
The replacement flights will usually be the next Finnair flight. If you want something else you will have to get in touch with them through the online chat or phone line. Expect to wait two hours plus to get through on the chat. But notionally they can reroute you in many different ways. They will try to find a One World option if they can, but if push comes to shove they are supposed to reroute you even on other carriers outside their network to try to get you home within 24 hours of the scheduled arrival time.
Note that there is no financial compensation for the inconvenience as strikes are regarded as outside the airline's control.


Think about what you want. Is an extra day in Rome not really a problem? Then go with the default reroute and claim for the hotel and food and beverage (no booze). If you really need to get back quicker, then be prepared to spend a lot of time and effort on it. Alternatively you can always cancel for a refund, but that is not usually the best option as then you are on your own to get new tickets which are often more expensive.