How do I move users from the current div after changing their role

I have two divs: speakers and audience. When someone asks to turn a speaker or to turn down to audience? I was thinking of send a channel message with a json objects:

{
  msg_status:"userUp";//user turns speaker
  userId: 123456
}

The problem is that Agora RTM does not allow to send the json object.At least, I’m not getting it