User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-1992639-20130307153033/@comment-4787430-20130308023111

You can switch to legendary skills more than once. I tested it, after I reached 100 in a skill (obviously testing with console commands) I was able to reset my skills/perks a second time. I just adds a number 2 to the side of the imperial (Legendary) icon. Image