FAQ Question #25
» How do I change my username?
Usernames of personal journals and communities can be changed for a $15 USD fee. This fee is charged because changing usernames is a complex process and can cause confusion for other users. If you have only recently created your account and have few or no entries, you may find it easier to create a new account instead.
It is possible to rename any personal or community journal to an unused username. Additionally, personal journals can be renamed to the username of another personal journal under your control; both journals will need to have the same password and the same email address. (This does not combine the contents of the two journals.)
See http://www.livejournal.com/rename/ to purchase or use a rename code. Once you have renamed your journal, it cannot be undone. The old username will be permanently unavailable for both future renames and new account creations.
If you want to hide your journal from someone who has found your username, the rename feature is probably not what you want. Comments and community entries that you have written will display your new username; people may also be able to find you based on your community memberships, interests, friends list, and so on. Instead, you should consider deleting your entire journal or making it Friends-Only or Private.
HOW RENAMES WORK
LiveJournal identifies your account by your user number, not your user name. Renaming an account simply changes the name associated with that number - everything else about the account remains the same. All existing comments in other journals and posts in communities will display the new username.
If you wish to rename a community, you can do so by selecting your community from the "Work as user" box and click "Switch" before performing the rename. You will need to be logged in as the maintainer account in order to do this.
You have two options for what will happen when someone tries to access the old username. The old username can automatically redirect users to the new username -- using this option is encouraged, so links to posts in your old journal still work. The userinfo page and journal page for your old username will automatically forward to the userinfo page and journal page for your new username, and any LiveJournal user tags will automatically display the new username instead of the old. This redirection will remain in place as long as your account exists. Alternately, the old username can be marked as deleted, so anyone who visits the journal will receive an error message. The old username will remain unavailable for at least 30 days.
As a convenience, you can also choose whether or not to preserve Friend-Ofs when renaming a journal. If Friend-Ofs are preserved, then everyone listing your old username as a friend will continue to list your new username as a friend. If Friend-Ofs are not preserved, you will be removed from the Friends lists of all other users when your account is renamed. (Of course, they can then add you again.)
You may also choose whether or not to keep all of your existing Friends and community memberships. If you choose to preserve these, your Friends list will be unaffected, and anyone you listed as a Friend will see your new username on their Friend-Of list. If you choose not to preserve these, your Friends list will be cleared and you will be removed from any community you were a member of.
Once you have chosen whether to redirect to your new username and preserve your friends and community memberships, you will not be able to change these options again.
How do I create an account? How do I get started?
How do I make all my journal entries Friends-Only, Private, or Public?
How do I delete/undelete my entire journal?