On the State dept website, it says that even if you've never had a passport card, you can count it as a "renewal" if you have a book. However, in the form, it looks like you need to send in your most recent passport book (
https://eforms.state.gov/Forms/ds82_pdf.PDF). I know that makes sense when you're renewing your passport book, but I have quite some time on my passport book, so it does not make sense to me that I need to mail that in. It doesn't say anywhere that they will send it back or how.
https://eforms.state.gov/Forms/ds11_pdf.PDF is the form for a first-time passport, but it's clear that this form won't work.
Has anyone gotten a passport card separately from the book? How did it work for you? TIA.