The associated Google account that you use to sign in to A2X can be changed and we've outlined this process below for you.
You can invite other Google Accounts, including another that you use - to allow multiple users to access a single A2X account.
Go to Settings > Users
From there, the users can be invited or removed. If you have a new email you use for logging into A2X, you can log in using the old email and invite yourself at the new email. If one is an email you no longer use, this is a nice way to clean emails that are no longer being used.
Here is how to clean up the user email:
If you are the Admin of the account, you can also 'switch admin' rights to the other user. Click on "switch admin" to your new email from the old one, once you accepted the invitation at the new email. Then from logging into A2X from your new email, you can delete the old email.