How do you change credit card on file? Have family sharing but it is authenticating me against the credit card that was retired. Not very helpful. I've logged in but it won't let me change it.

Hello BusArch,
I understand that you want to updater the payment information on your Apple ID that is part of Family Sharing. Let's see if we can get that done so you can have an updated payment information.
To make sure we are on the same page, you should be able to change the payment information as long as you are the Family Organizer and can only use a credit card or debit card as a form payment. I am not sure what steps you have done besides logging in, but take a look at the article below for the steps to change that payment information.
Change or remove your Apple ID payment information in the iTunes Store
https://support.apple.com/en-us/HT201266
Take care