It depends on how much the dealer knows or is willing to listen. Back in the day it was a bunch of paperwork through Tesla and a very manual experience, nowadays it's 10 seconds via a webform. You enter an email to transfer ownership to, they click an accept link, and it's done. A lot of them don't know that and won't listen.... just sit right back and you'll hear a tale...
I sold a MYLR to a dealer last year and asked them repeatedly for the email address that they use to accept Teslas into so I could transfer ownership to it. They told me they'd get it to me, so I told them I'd wait, but not to supercharge the car because it would charge ME until they accepted ownership of it. A couple weeks go by, I called the sales guy I dealt with and told him that I could (in theory) just walk up to the car with the app and drive away with it if I wanted to, and they really should provide a Tesla account for me to transfer to, it would take less than a minute. He laughed and told me they "were working on it", then I get a notification a day or so later they're charging at a high usage SC and limit was set to 80%, lol. I called them again immediately, they apologized and told me that they have to go through Tesla to change ownership after someone buys the car (which is the way it was in the bad old days). Every couple of days I'd check on the car, and it was still on the lot, until one day it was in someone's driveway. A couple days later, I got a transfer of ownership request from Tesla with the person's full name, to which I immediately processed (in less than a minute, again lol). They had it listed for about $15k over new at the time, so I'm surprised it sold at all, haha.
So, because the dealership was willfully ignorant and wouldn't listen: I ended up paying a couple of bucks for them to charge the car, I learned the home address and name of the buyer of my car (a significant privacy concern), and the other person had to wait a few days to have the car show up in their app. All they needed to do was create a free account on tesla.com, lol
