Canceled flight how long before need to deal with (Dec)

Gail, I don't now if my experience is generalizable, but this year we flew Tulsa - Paris, then returned Bologna - Tulsa. I bought our plane tickets in late November of 2021. In December, BA changed my flight times, leaving an impossible connection at Heathrow (20 minutes!) I pretty much let it go, thinking it was so ridiculous that the computer would catch it.

Then in February, I had another notice saying the times were the same, but there was now a terminal change! Still with 20 minutes from landing at LHR from Bologna, and taking off from LHR to Dallas. Well.

Again, I kept checking, and it kept being the same impossible connection. I kept checking flights and finally found a combination that I thought would work for us. I called BA in April, and drew the service reps attention to the connection time. "Well," she said, "obviously that isn't going to happen!" And she found me a revised flight plan that was better than the one I had come up with. This was less than a week before we left the US for Paris.

I suspect waiting several months is not your best option; I got lucky. I do suggest you call the airline, and ask. I've always had good experiences talking to airline personnel.

I think you can drag this out into December and claim ignorance. The downside is that if you decide to take the trip at the last minute, your chances of correcting the dates and get better flights/dates/routings may shrink

Thanks for sharing your experience. So far, this is the 2nd change. The prior one was a change in the airport which actually worked out well for us. If I didn't check, I wouldn't even know these changes were happening. Oh well. I'm thinking there will probably be more shifting around before December. I can work with the current flight. I contacted my accommodation and added another night just in case.

My big concern is waiving my right to a refund due to a significant change if I wait too long.

Gail,
I agree with Jane, call KLM. You could also try checking their website before calling which might possibly be quicker. Not sure about KLM but United and, although difficult to find, American both list their cancellation policies on their websites. Even better, you could Google European airlines cancellation rules which hopefully will show your options. The good news is that if a European airline changes or cancels your flight I believe you're entitled to not only your money back but also, if you do decide to travel and arrive later than scheduled (maybe by 2, 4, 6 or 8 hours) you are entitled to a monetary compensation. I once had a Lufthansa flight departing from SFO changing planes in Frankfurt and arriving in Paris. At the airport we were informed that the flight would be delayed because the plane was evidently "missing a part". Don't even want to think what that might have been. They said we would be delayed but didn't know by how much. I called Lufthansa customer service and a helpful agent got us onto an Air France nonstop from SFO to CDG instead. When I returned home I emailed Lufthansa asking them about compensation as we arrived about 4 hours later than scheduled. They did not reply to my email but did send us a check for $800 +. Worth knowing about. Bon chance!

I think you can drag this out into December and claim ignorance.

That has to be the worst idea I have seen in a long time.

Ask the folks who got fined for not validating their train ticket how well the ":I didn't know" excuse works.

Contact KLM now and find out what your options are, is my suggestion