The Rover-Landers of BC

I have a fellow in Washington interested in buying my P38. Wondering how this would work?
If you sold a car to WA, did they come and pick it up or did you drive it down there to make the sale?
Any advice appreciated.
Thanks
Gordon

OK, I did my homework. ICBC agent tells me I just need to fill out the usual transfer of ownership and also a bill of sale. Each of us keeps a copy. The buyer has to deal with a temporary permit and border details.