You do not lose your rank, some people had issues with that with another issue, but I am guessing not. I am not 100% sure so you might want to ask someone else.
I changed my name and didn't lose my rank, so i'd presume not. But I would have proof just in case if you do change your name - receipt, ss rank before name change etc
Pretty sure you don't lose your rank as your unique ID for your account follows you, but just like it was said before, have proof just in case.
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