If you no longer wish to own a discussion, you can transfer ownership by promoting another user to ‘Owner’. To do so, go to the discussion menu (click on the three horizontal bars at the top-left of the screen), and select ‘Discussion Settings’. Select the ‘Invites & Permissions’ tab, and use the drop-down menu by the relevant user’s name to promote them. Note that in order for a promotion to Owner to take, the new Owner has to accept or reject the ownership transfer.
There may be only one Owner per discussion. Once ownership is transferred the initial Owner will turn into an Admin.