You didn't read the story I guess. We don't appoint witnesses, it's up to you to pick them. Rogier is the first candidate, more will follow. The Byteball network belongs to the users, they decide who they want to be their witnesses. In the startup phase Tony had to run all 12 because we didn't have any candidates yet. So this is a big deal, it's step 1 in the community taking ownership over the platform, also known as decentralization. I could post here how you can change your witness list but blindly changing it without checking out the candidate is worse than leaving the switch on auto-update from hub. So I suggest you read the article and make an informed decision yourself.