https://www.siliconvalley.com/2022/04/04/travel-troubleshooter-can-i-be-charged-an-extra-1360-for-changing-my-flight/

DEAR TRAVEL TROUBLESHOOTER: Last year, I booked a ticket from San Francisco to Munich. A few weeks later, Lufthansa informed me that the flight had changed, and that there would be a stopover in Frankfurt. Given that, it was more convenient for me just to terminate my flight in Frankfurt than to continue on to Munich.

I called Lufthansa and asked to change the ticket to Frankfurt, confirming that the change did not increase the price. I did that on the phone, noting the time and the representative I spoke to.