For that you would need to set up a websocket to listen for real time updates on server. This is not currently implemented in Wappler although it’s on the roadmap.
As a workaround you could use the scheduler to poll the database every x seconds and show a modal when a condition is met. It won’t be realtime but it’s that, implement sockets yourself or wait for the native implementation in Wappler.
The third option is server sent events which is similar to polling. You would need to build it yourself too.