You can not change your credit card but you can do the following: simply cancel the automatic renewal of your current subscription and sign up for a new PLUS subscription with the new credit card. This way, the old card won't be charged again. The new subscription will start with the expiration of your current one.
For an overview of your PLUS transactions, click your profile picture (top right), open the menu 'Upgrade to PLUS' or 'PLUS Member' and select 'Transaction history'.