I GM a game. It's not a roleplaying game, but a discussion game. I no longer want to be the GM/owner. Some of the other members have expressed an interest in becoming GM/owner. Can I give ownership of the game to one of them?

Yeah, under Edit Players click a name and Edit (Wizard) has a dropdown that says something like "player". You can click it to make it say GM.

How do get removed from the game afterwards?

Have them remove you.

If there's any problem with the process, rMail the mods and explain the situation to them and they can help you out (but, wait until you actually have a problem...they don't like being the first resort if there are other options available to handle issues.)