javascript - How to unsubscribe an app from a page for facebook webhook lead ad?

Question

I have the following function (taken from the facebook webhook tutorial) for subscribing an app to a page, but I want the reverse thing to happen ( unsubscribe).

How can I do that? I have not found any answers yet, in JavaScript.

function subscribeApp(page_id, page_access_token) {
        console.log('Subscribing page to app! ' + page_id);
        FB.api(
            '/' + page_id + '/subscribed_apps',
            'post',
            {access_token: page_access_token},
            function(response) {
                console.log('Successfully subscribed page', response);
                // insert in DB
            });
    }