If you have opted to make a Regular Donation to a TryBooking Fundraising page, the card that you used for your initial donation will be the card that is used for the subsequent payments.
If your card details have changed, you will need to cancel the Regular Donation that is linked to your old card and submit a new Regular Donation to that Fundraising page using your new card details. Your confirmation email will state the last 4 digits of the card linked to your Regular Donation.
For instructions on how to cancel your Regular Donation see: How do I cancel my Regular Donation
If your card has been cancelled and you don't actively cancel your Regular Donation, the next autopayment on your Regular donation will decline. As a result, your Regular Donation will be cancelled, ceasing any future payments to that card.