I'm a little confused by the custom domain option when you want to host a landing page on Convert Kit (the ck.page one). It seems you can either create your own page url name or not. (why is there even an option for not renaming it yourself?) I already made my landing page and forgot to edit the page name so now my links I've been sharing all have random numbers and letters in it which doesn't look good. Can I go back in there now and edit the page name or will this screw up all my existing urls I've already shared?