1. Login to https://outlook.live.com, using your existing user name and password. You will be on Outlook home page. The left side of the page highlights your email options, and the right side details your profile. Click on your user name, you will see set of options.
2. Click on "Edit Profile." You are now on the Details section of your account. From here you will be able to add/modify your personal settings including social networks, work and education history, and contact information.
3. Click the "Edit" link below your current user name.
4. Fill in both the first and last name fields. Click "Save" to store your changes, and you will be directed back to the Details page. Your user name has now been updated.