You 'sell' the vehicle to yourself and your son. Fill out the title as if you are selling it and put yourselves as the buyers. If you want to update the registration, you need to do it in person at a DMV office. For title only, you can mail it. https://dmvnv.com/title.htm
That is a question for the actual DMV, not Google helpers. I imagine he'll need to bring everything you needed for your original title.
Thanks! Your answer is awaiting moderation.