Yes, I have. But it's an awkward workaround.

(Caution: I'm an MVP Gold and immune from change fees, so YMMV.)

It's not technically "reissued." It's basically encased in amber for reuse.

If you change more than 60 days from the date of travel, AND the companion has no status (sorry, spouse), you can reuse the companion cert by calling in, having the reservation split, and then re-deposting the primary traveler's airfare into My Wallet and keeping a record of the companion traveler's ticket number separately.

Then, to reuse the companion cert for the same companion on a different itinerary, you need to phone in and make the primary traveler's reservation, and pay with a credit card for the primary traveler's ticket. No My Wallet funds can be used. Then the companion's cert and fees are reattached and any difference in fees and taxes are collected/refunded.

It's very awkward, but it is possible. I've done it.

If the primary traveler decides that he/she does not want to reuse the companion cert after canceling the original reservation (as long as it's done before the value of the companion cert/fees/taxes expires), the value of the fees/taxes of the companion cert can be redeposited into the primary traveler's My Wallet. But the cert itself is forfeited.

Yes. There will be a quiz.