How to change your profile name
Your display name lives on the Profile Info tab. Open it, edit the field, click away, and it saves on its own.
Three quick steps
Open your Profile Info. Use the button above, or click your avatar at the top right and choose My Profile. The Profile Info tab opens by default.
Click the name field and type. Click into your name, clear it, and type the name you want to show.
Click out to save. Click anywhere outside the field (or press Enter). It saves on its own, so there is no separate Save button.
If your old name comes back, refresh the page and try once more. If it still will not stick, contact support.