1. Sign in to Facebook and navigate to Account Settings page.
2. Click Edit link correspond to Email setting.
3. Now click Add another email link.
4. You will be able to see a new text box with the label New Email. Enter your new email in that field.
5. Before save changes, enter your Facebook password in Password field.
6. Click Save Changes button.
Note: If you didn't get any confirmation email you can resend it from Email setting tab.