Hello @rebeccaenglandco,
Welcome to the LastPass Community
It sounds like you may have set up an account under your alternate email address at some point in the past. Regardless, if you can access that address, then you may easily delete the account in order to change the current login to that address.
I've tried to sign in with it, it says to check the email address, but Lastpass doesn't send anything.
When my new client shared those passwords via Lastpass to the other email address, it's asking me to create a new account. If I have 2 accounts, I'll have to continuously switch back and forth which is counterproductive for me.
This account in question was originally set up using that email address many years ago, but was changed for privacy reasons a few years ago. It is no longer on the account anywhere (not even as a back up email).
