Rasa scheduler reminder how to return a message to the client, such as an app

I want to use rasa to make a schedule reminder now.I sent a request to rasa. URL is http://localhost:5006/webhooks/rest/webhook request body is:

{
  "sender": "rasa",
  "message": "Remind me to go to the meeting after one minutes"
}

But the schedule is up, I want to send a notification to the client, such as the app, to remind the user what to do.

How can I do it? Is there any way to achieve this? Thanks a lot!

Note that your schedule-based code needs to know the conversation_id which you can set when you first create the schedule for the user.