In my Quicken account I have a credit card linked to it with which I can make automatic payments when my quicken account is updated. I need to change this to new card since I am about to cancel the present card.
All you need to do is log into your online Quicken.com account. Then click on the link for "Manage your Quicken & Simplifi payment methods on the Payments card. You should be able to change the credit card to be used for future payment there.
