Tentatively accept event

{
  "type": "object",
  "required": [
    "event_id"
  ],
  "additionalProperties": false,
  "properties": {
    "event_id": {
      "type": "string",
      "description": "Id of the event."
    },
    "comment": {
      "type": "string",
      "description": "Response message to the organizer."
    },
    "sendResponse": {
      "type": "boolean",
      "description": "Send a response to the organizer (default true)."
    }
  }
}