Now that I'm in front of a keyboard, I can tell you how I as a Spooky pre-order buyer sold my spot, and how I bought a spot.
I put down a deposit on a Rick and Morty day 1, minute 1 in the original order window and got BSE# 374. I don't remember the exact ammount, but I want to say it was a $1500 payment direct to spooky. Several months later, COVID hit, and in the weird window at the beginning of it, I wasn't sure I was going to be able to work and had to cut back on spending. I couldn't ask my family to cut back on things like eating out while I had a pinball machine pre-ordered, so I elected to sell my spot. I ended up selling to my boss at work. He paid me $1500 in cash, and at that point I emailed Spooky and directed them to shift the pre order from me to him. They asked for confirmation (and tried to make sure I wasn't getting screwed), and I confirmed that yes, its a real person and I have the money. That was all that was needed. 6 months down the line he decided he didn't want it and offered to sell it back, which I happily bought. I paid him directly , he emailed spooky, and they shifted the pre-order back to me. At no point did the person buying the pre-order from the owner of the pre-order have to pay Spooky anything.
I hope that helps and good luck!