@Navita A, Thanks for posting in Q&A. For your issue, I am not familiar. Then I go to do researching and find we can change the legal name follow the steps in the following link:
However, if it still not working, you can submit the thread in the following forum to ask for help. https://learn.microsoft.com/en-us/credentials/support/help#how-to-post-a-support-request-in-the-forums
Thanks for your understanding.
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