To transfer WordPress.org plugin ownership to someone else:
- Update the plugin’s readme.txt file, changing the Author, Author URI and Contributors in the plugin header and commit those changes to the SVN repository.
- Log in to wordpress.org and navigate to your plugin’s page. Click the “Advanced View” link in the right sidebar. From here, add and remove any committers in the right sidebar. If you’re going to remove yourself, just be sure to do that last since after you do, you’ll be unable to make any further changes.