To change the email address on your account if you do not have access to it, you will need to create a request to recover the account. Currently, you can only do this if you are not logged into any Epic Games account.
- Open your browser in incognito mode so that you are not logged in to any account
- Follow the steps here: How can I recover access to my Epic account?
Note: You may need to use a previous username and password combo to follow the linked steps