If you tell me which Windows 11 edition you have (Home or Pro) and whether the account is local or Microsoft-linked, I’ll give the single best step‑by‑step path tailored to your setup.
If you absolutely cannot sign out right now (e.g., you’re in the middle of work), use the Local Users and Groups manager. This method changes the name immediately without forcing a logoff, though you’ll need to lock your screen to see the effect. how to change the name of my local account in windows 11 hot