Acessing return value from gateway event scripts

I have a gateway message handler
I want to return message part of this payload using system.util.sendRequest()
But I’m getting an error using this function,How to solve it

gateway Message handler script
script using send system.util.sendRequest()

error message

You aren’t providing a payload when calling .sendRequest(). So the message handler in the gateway is naturally not finding anything in payload.

But how to give the payload Msg in previous message handler script in gateway