Martyn is right about not completely removing him - but I'd also advise against "recycling." Since WikiTree is shared, someone else may be using that data. Changing the profile completely pollutes any connections or links that may have been made within WikiTree or anywhere on the Internet. Probably the best idea is to disconnect him from your tree by severing the relationships that attach him. Then if you don't want him in your Watchlist, you can click on the "Privacy" tab on his profile, and choose to remove yourself as a manager. This "orphans" the profile in that nobody is managing it, but it preserves any information and sources that the person who originally entered it shared in case someone does want to add that profile to their tree later.