Other people have told you how this "account update" process works so I'll skip that. I just went through this with Citi/Mastercard. I'm not sure if other com

Other people have told you how this "account update" process works so I'll skip that. I just went through this with Citi/Mastercard. I'm not sure if other companies do this, but I was able to opt out of this "account update" feature to hopefully stop a Comcast charge from going through to my new card number. I'll find out on Dec 10 if it works, but the customer rep I spoke to says it should. It basically cancels that feature so that I now have to manually go through every merchant and update them to my new credit card.