If this is a personal Microsoft account, the supported path is:
- Go to Manage how you sign in to Microsoft and sign in: https://account.live.com/names/manage
- Select Add email.
- Add the new email address and complete verification.
- Select Make primary for the new alias.
- After the new alias is primary, remove the old email if needed.
Important details:
- A primary alias cannot be removed until another email has been added first.
- Verification codes sent by email can only be sent to the primary alias or another email added as a sign-in verification method.
- If the option to make the new address primary is greyed out or blocked, some accounts have restrictions that prevent changing the primary alias directly. In that case, use Contact Microsoft Support.
- If the old email is already inaccessible, add and verify the new alias before removing the old one.
If the issue is on a Windows 11 PC sign-in and the goal is to use a different Microsoft account on the device, one documented workaround from Microsoft Q&A is:
- Go to Settings > Accounts > Your info.
- Select Sign in with local account instead.
- Restart the PC.
- Go back to Settings > Accounts > Your info.
- Select Sign in with Microsoft account instead and use the preferred email.
- Restart again.