These are details you gave when ordering the game online, right? I don't think you can modify this (the only UI are at www.wincustomize.com and in SDC) - if you really want to, you'd have to email support asking someone to manually make the change.
However, what you can do - based on an earlier post - is make a new, 'anonymous' account with the details you want and using your serial no, and then link it to your metaverse stuff, which would have the same effect. AFAIK, there is no loss of fidelity or anything. Let me know if you need more details and can't find the earlier post.
~SDC~
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