I was in a few situations where I had old WordPress websites without an actual URL. This happened because of a cancel or change or just starting over. I wanted to access these sites and change them over. I learned quickly that this is actually quite easy.
1. Add the below code to your sites functions.php in the theme directory.
update_option( 'siteurl', 'http://example.com' ); update_option( 'home', 'http://example.com' );
2. Then access the website with that URL. https://example.com/wp-admin
3. Once you get to the login and login, you will need to update all the URLS that your website is currently looking for. I tested out a few plugins but ended up using Go Live Update URLS’s’
Once I did that, I was back in business.