Can Yahoo! change group ownership?
Yahoo! is unable to transfer ownership of groups in Yahoo! Groups. Only the current owner of a group is allowed to transfer ownership. If you need to request the transfer of group ownership, you will need to do so by contacting the group owner.
If the owner of the group is unavailable or cannot be contacted, current moderators can always assign full privileges to another group moderator so that they can process owner related tasks, or create a new group and invite members to join.
In the event that there are no active owners or moderators in your group, Yahoo! may be able to assign moderator privileges. For more information, please see our help article about groups with inactive owners or moderators.