I am having a real issue with this. When I first set up my blogs I had to choose the permalink structure 'post ID'. I want to change this, or ideally have the ability to select permalinks for a post without the need of changing all of the previous url's of my posts, which is what happens when I change the site wide permalinks. Unfortunately, because I have post ID as my permalink structure, modifying the page slug makes no difference to the post url. I know I can change the site permalinks after which do 301 redirects, but these are quite established domains with lots of the posts indexed, I Really don't wish to risk losing their index, or ranking?. Cheers