I need to update my payment date for my applecare

If you're talking about the day a subscription renews, you would have to cancel the subscription, wait for it to end (expire), then start it again on the desired date. Note that for some subscriptions this may entail loss of data (such as playlists for Apple Music) or other features.

View, change, or cancel your subscriptions - Click on the link to learn "How to cancel a subscription from Apple." --> If you want to cancel a subscription from Apple - Apple Support

I don't think there is any provision for that.