title: Changing application server key in push manager subscription
body: <p>I implemented web push notifications using service worker. I collected user subscriptions with a particular application server key. Suppose if we change the application server key, then when we get the subscription using "reg.pushManager.getSubscription()", we will get the old subscription information which was created using the old application server key. How to handle this scenario? How to get the new subscription from the user?</p>