Here’s the step for resetting the password (but because your email is no longer in use, you still need to be able to change the email address in your database):
1. Go to your WordPress Login page (something like https://yoursite.com/wordpress/wp-login.php)
2. Click on the Lost your password? link
3. You will be taken to a page to put in some details. Enter your username or the email address on file for that account.
4. Wait happily as your new password is emailed to you.
5. Once you get your new password, login and change it to something you can remember on your profile page.
Reference: https://codex.www.ads-software.com/Resetting_Your_Password