I think it could be possible to create a new class of common stock (like B shares) that have different rights and sell them in the market or to a few large investors.
One thing discussed (which I don’t think happens because it’s complicated) especially in regards to setting them up as a utility would be to transfer the assets to a “Newco” then the original stock is the legacy and they can issue new with different classification. Because of the sensitive nature and size of the bond market I don’t Think they go down that road but who knows.