Originally Posted by
Weltrekord
To be precise: i don't touch the first segment and i only change the date of the following segments it should be free according to my understanding? That's what i understand out of paragraph 16a.
Nope. Many fares have similar wording. The fare doesn’t lock until the first segment using that fare basis is flown. If you make any change of any sort before flying the first segment it will trigger a refare.