Handling a Game That Was Renamed

A few months ago, Horizons: Empire of Istaria was officially renamed to Istaria: Chronicles of the Gifted. Since there's already a page here for Horizons, whats the expected way to handle the new name? Create a new page? Make the new name an alias? Make the old name an alias?

Has this already been dealt with in another game here?

Just make a name change request in the stickied topic in Delete & Combine Requests. And the old name should be the alias, IMO.