Move Existing game to another account

Is there a way to move an existing game from my account to a friend's account? Like a transfer of ownership?

Not really, technically you could download assets and transfer them outside of Roll 20 and upload them to another account, but that would only be artwork, and probably a violation of the Service Conditions. Infringement of copyright is a serious matter and they can't allow transferring of I.P. even with permission. This is all pretty clearly spelled out in the User Agreement. When you purchase a product you have very limited rights to provide that product to someone else whether there is consideration or not. If you think about it this is a good thing. As anyone who makes their living via creating should agree.

I think he's asking about moving a game in progress, not purchased content from the Marketplace. OP, I'd open a support request with Roll20 and ask.  If it's possible, it's something they'll have to do manually is my guess.  If the game relies on any purchased content, they may not be able to transfer it or it might transfer absent that content which may or may not bork things.

Jesse has the gist of it. When I transferred the ownership of my group I had to supply the game's name, who I was transferring it to, am I also transferring any purchased material, and why I'm doing it. What it boils down to is that they can do it but if it contains any purchase material such as module, addons, or tokens/tiles, they would probably need to be transferred to the new owner's account and removed from yours. If you do not want to give up any purchased material in the game then you might want to consider just making the other person a co-gm and creating you a bookmark where you can enter the game as a player. The how to is in the tips and tricks thread.

To clarify: I have a pro account.  In one game I created, my friend has DM access since he . . . well, he's the DM. Recently, he got his own Plus account for more storage space. Currently, I am unable to play in that campaign, but as the game creator, I still have to basically curate the game. Since my friend has his own plus account now and doesn't rely on my dynamic lighting etc, it would just be easier for him to have creator access.  Rather than rebuild from scratch, we'd like to just move things over. I'm not looking to transfer assets, just the game.

There are some work arounds but they take a little bit of effort. Enable the character vault and assign all the characters to the person who is taking the game over so they can use the vault to move them into his vault then into his game. If you have one image maps, you can use a character sheet to move them also if you assign them as a token to the sheet. It does not work with maps made with tiles as it has to be one image not lots. Handouts takes two tabs open and you have to cut paste text between games. Easiest way is to contact the Roll20 team and talk to them. They might have better ideas.