lightning__conversationEnded

import { LightningElement, wire } from 'lwc';

import {
    subscribe,
    unsubscribe,
    APPLICATION_SCOPE,
    MessageContext
} from 'lightning/messageService';

import ConversationEndedChannel from '@salesforce/messageChannel/lightning__conversationEnded';

export default class ConversationEndedExample extends LightningElement {
    subscription = null;
    recordId;

    // To pass scope, you must get a message context.
    @wire(MessageContext)
    messageContext;

    // Standard lifecycle hook used to subscribe to the message channel
    connectedCallback() {
        this.subscribeToMessageChannel();
    }

    // Pass scope to the subscribe() method.
    subscribeToMessageChannel() {
        if (!this.subscription) {
            this.subscription = subscribe(
                this.messageContext,
                ConversationEndedChannel,
                (message) => this.handleMessage(message),
                { scope: APPLICATION_SCOPE }
            );
        }
    }

    // Handler for message received by component
    handleMessage(message) {
        this.recordId = message.recordId;
    }
}

({
    onConversationEndedEvent: function(cmp, evt, helper) {
        var conversation = cmp.find("conversationKit");
        var recordId = evt.getParam("recordId");

        console.log("recordId:" + recordId);
    }
})