Originally Posted by VegasGambler

To be really clear (and I know you know this, but other readers may not) they are "at least one segment must clear by".

Also my understanding is that if at least one segment has cleared, you can change and every segment will be waitlisted on the new itinerary, and they will not expire (unless they don't clear; then they are gone). Is that not correct? Do you need availability on at least one segment at the time you make the change?