If you go to Safari > Preferences > Autofill and select Credit Cards, Edit..., you can see which cards Safari remembers. You can change or delete any of them from there.

Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365