Want to share a recent experience. MNL-KUL-BKK. I’m Plat on flypass, P2 is no status on flexi fare. We’re on the same flight to KL but P2 is on later flight to BKK. P2 tries to Go Show leg to BKK, but unsurprisingly MNL ground staff is unaware and untrained on go show. After a bit of back and forth, ground staff concedes but P2 still can’t go show since all earlier flights are oversold. They did let me to switch to a later flight without charge to allow us to fly together. Don’t think this is usually allowed but the oversell might have otherwise permitted it.

In KL tried to waitlist/standby an earlier flight to BKK in case of no shows. F check-in desk, main terminal transfer desk, and satellite transfer desk all claimed waitlist/standby is not possible for earlier flights.

So outstations can modify subsequent legs on connecting itineraries and moving to later flights is possible on oversells. I did read one comment allowed standby/waitlist to SIN when trying to go show a full flight, but unfortunately I wasn’t successful during 4 attempts.