To change your email address into an alternative one, you need to do the following:
Go to your profile in the top-right corner.
Choose Account settings.
Under the Profile tab, you will see your current username and the email address, which is used as primary one.
If you need to change any of these fields, just remove the previous data and type in the new one.
To confirm new or existing email, click verify button below the email input field. The verification email will automatically be sent to the listed email address.
Once you receive it, click Confirm email address within the email and login again.
All the changes will successfully be saved.