Official advice is inconsistent.
I contacted NPIC@state.gov to ask this:
I have a question about passport renewal. I currently hold both a
passport book and card, both valid, and am eligible to renew by mail.
I would like to renew the book only, while keeping the card in my
possession in case I need it in the meantime for identification or
Am I allowed to submit DS-82 to apply for a passport book only, and
submit only my passport book? If so, should I still list my current
passport card number on the form? And will my passport card remain
After a first reply which was annoyingly non-responsive (copy/pasted irrelevant instructions from the website which did not address the question), I received the answer:
To be eligible to use the DS-82 renewal form by mail, you must submit the most recent passports (and
it has not been lost, stolen, mutilated, or damaged) that was issued when you were 16 or older and
issued within past 15 years (counting from ISSUE date). Also, include a note with your renewal
application to NOT cancel the card and request that it be returned.
Which is still not very clear, but does make it sound like you have to submit both the card and the book if you have both, even though you may only want to renew one. You can have the card returned instead of cancelled, but that doesn't really help, as the whole point of doing this would be to keep the card in your possession, and valid, while the renewal is being processed.
Update: After I received the above answer, another email arrived from another agent with a different answer:
IF BOTH passport products are still valid:
If you have both passport products and they were issued at the same
time but only want to renew one of them, you will only submit the item
you want to renew with Form DS-82.
If you have both passport products and they were not issued at the
same time but only want to renew one of them, you will only submit the
item you want to renew with Form DS-82.
That is more explicit, and more in line with what we would hope, but it is confusing that the agent says "it depends" and then reaches the same conclusion ("you will only submit the item you want to renew") for both cases. I wondered if they made a copy-paste mistake and meant for one of them to be different, so I sent a reply requesting further clarification.
In reply to the previous message, I received two separate responses. Agent #2097 wrote:
You may renew the passport book and card seperately. If you are renewing your passport book only, submit your most recent passport book with the DS-82
And a few hours later, without any further prompting on my part, Agent #100318 sent:
Yes. You must submit both even if you only want to renew one of them, doesn't matter which one.
And the next day, yet a third agent (#150023) weighed in:
You CAN send your passport book in for renewal and keep your passport card for travel. We suggest
that you include a letter with your renewal letting the agency know that you have your card in your
possession and that you have kept it for upcoming travel.
So, these directly contradict each other. It seems that even the authorities themselves don't know the answer to this. But the majority seem to think this is allowed; maybe Agent #100318 is just wrong. Nevertheless, if you try it, there may be some risk that your application is processed by someone in Agent #100318's camp, with unknown consequences (though none of these agents have suggested the worst-case scenario, that your passport card might be silently revoked).
(Side note: the agent numbers are pretty funny, like something from The Prisoner or Get Smart. But I'm skeptical that there are a hundred and fifty thousand people answering emails for the National Passport Information Center. :)