From the Profile menu, select Edit Profile then on the page that opens click on the Account tab and you can change the name everyone on the website sees you under Your Name
You can't change the name you use to login with but that's not seen by anyone other than you. If you do wish to change it and/or tidy up your accounts (I see it looks like there are at least three accounts that could belong to you) let me know what login name and email you wish for your account and if you are using the other accounts.
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