Schedule an Update or End (LiveActivities)

I hope I'm just missing something

is there a way to schedule when a Live Activity should be dismissed, or schedule when its content will change? (local, without a server)

I have observed other apps have the ability to swap out their countdown view for a 'timer complete' all while the app is backgrounded and airplane mode is on (ie its not being updated via server)

however when trying to build any kind of similar functionality into my own app I come up short, I see no way to schedule when a live activities view will change,

and similarly no way to schedule when it should be dismissed, and the system doesn’t treat the stale date as a flag for clearing an out of date live activity