There are two ways to change or transfer folder ownership to another collaborator. Through the Collaborators menu in the right pane of a folder or from the Collaborators page of a folder. If your folder only has a few collaborators the Collaborators menu will probably work best. If you have a long list of collaborators and you need to find a specific one you may want to use the Collaborators page.
Some things to consider:
To change or transfer folder ownership, you must be the owner of the folder.
Once ownership is changed, the collaborator you designate will be the new Owner of the folder and your access level will be downgraded to Editor. The contents of the folder will no longer count against your account's storage allowance.