Your account's primary alias appears on Microsoft devices, such as the Windows 8 PC, Xbox, and Windows Phone.
When you rename to a new primary alias, you keep all your data - such as your inbox, profile information, and contacts. You will no longer be able to use the old primary alias to sign in or to send mail. Learn more about account aliases.
It might take up to 48 hours for your new primary alias to appear across all devices and services.