How do you plan on managing the trade? It's not really possible to transfer reservations to another party after the crackdown on campsite reservation scalping. The trick that the scalpers used was to cancel then immediately try to rebook the site because it went right back into the recreation.gov inventory. That no longer works because once a campsite reservation is cancelled, it would have to be manually released back into the inventory by a park ranger at the campground office.
They check ID now at checkin, and the name on the ID has to match the reservation. If you arrive late and don't checkin by morning, they could conceivably cancel your reservation and ask you to leave. You'll need parking passes and I believe these are matched to the campsite with license plates noted. I suppose it might be possible for a trade to occur after checking in, but that might look suspicious. Most of this was to get around the reservation resale, although specifically an even trade probably wouldn't be a violation of the regulations. However, the system is now set up such that transferring reservations is near impossible.
The other problem is that you're unlikely to find anyone here with those exact dates. Your best bet would be to arrive early and go to the Valley Campground Office at the Curry Village parking lot. That's where I went to sort out an issue where I just wanted to inform them I'd be late a day and didn't want them to cancel my entire reservation as a no-show. I got a call back asking if I'd be willing to let them resell that night. I didn't see an issue, and they said the only problem should be that I probably couldn't come to the campground until after the checkout/checkin time of 12 PM. So after I'd agreed to that I checked on my reservation, which said that my four night reservation had become a two night reservation but with my last two nights gone. Turns out whoever changed the reservation screwed it up pretty bad. When I called the office the supervisor said that I'd better come in and they'd sort it out. I also had an option to immediately try to book several dates they said they'd make available and they'd cancel my previous reservation without a cancellation fee. My original final two nights were released into the inventory and snatched quickly.
I get there, and they said they would help me out by canceling the entire remaining reservation without penalty and booking the three nights I was staying. They had a list of available campsites, and picked one at Upper Pines that they said was really nice. It was also a big show, with one ranger each at two computers - one to release the availability into the inventory, and the other to immediately lock in the campsite and dates. They told me they had to work that way, because held back inventory is available to anyone (including on recreation.gov) once it's released. There might have been a few seconds when someone could have conceivably booked these nights. While I was there the group behind me already had a reservation at North Pines and wanted to be closer to friends at Upper Pines. The ranger apologized to them, and I had priority because someone cancelled my nights, while this group just wanted to change location.
OK - long story, but I'm just saying perhaps your best option would be to see if you can change your reservation at the campground office. They sometimes will have inventory available but held back for whatever reason. My understanding is that most are nights that have been cancelled but there are other reasons.
