No Call for Live Activity to update

In widgets when the button is tapped, we will get a call back to perform() func in app Intent. After this perform func execution is completed, timelineProvider will be called. Likewise, what is the option to update the live activity value once perform() is called in appIntent? I tried to access the live activity instance from the extension into the app, but it is nil so, I can't able to update my live activity.