For security purposes, it's not possible to change your email. However, you can easily delete the account you no longer want and sign in with your new email.
Here are some guides that may help you:
To delete your account, please check this guide: How to delete your account?
To sign in, please check this guide: How to Login to Haystack News on my Smart TV or connected TV device?
To configure your account, please check this guide: How to configure Haystack News?
Happy watching!