DECLINED CREDIT CARD
If the card was declined and a new card is entered, the invoice will have to be sent out manually. The new card will be saved and used toward future invoices for that subscription.
The way we store payment methods is via tokenization. We take the information entered, send it to our merchant service partner, and they send back a token of that payment method. The "token" is essentially designed to show that the payment method is valid, without saving the detailed information within WH.
So, if the card information needs to be updated, we normally rely on our credit card auto-updater. The customer needs to have an established payment history with you for 6 months, with no charge backs. Since this doesn't apply to this specific contact, the card information would need to be entered again.