I dedicate this turotial to cakblogs from WP support forums.
This happens quite often to me, when some old clients comeback asking for changes, but it turns out that they have lost all credentials to the website.
This is quick tutorial how to resolve this issue.
1st and maybe most the difficult part for someone that has very little experience with website development, is to find access to phpMyAdmin. This vary on every individual hosting provider, but if you can’t see phpMyAdmin somewhere in your hosting control panel, feel free to contact your hosting provider, or research your hosting’s support threads/FAQ section.
I can show example with WHM & cPanel which is very common hosting platform choice within many hosting providers.
1. Login to your WHM (if your hosting provider do not use WHM & cPanel skip to point 5.)
2. Once cPanel is open, filter down sidebar options by typing “list accounts” in the search field. Then click “List Account” button in the sidebar.
3. It will open the list of all websites that you have set up on your hosting. Find website in question and click cPanel logo.
4. Once you open cPanel, you should see phpMyAdmin button in “Databases” section. Click on the button. And this will open phpMyAdmin interface for you.
5. If you use cPanel you won’t need to login to phpMyAdmin, if you use something else you might have to login to phpMyAdmin. If you don’t know database logins you can always find them in wp-config.php file.
On the left sidebar in phpMyAdmin panel expand your database tables (if it’s not expanded already), and find wp_users table. The wp_ prefix might be different depending on your setup. Find your admin user.
This either will remind you the email (if you have access to the email, jump to step 6.), and if you no longer have access to the email, simply double click on corresponding user_email field for your administator account, in this case it would be firstname.lastname@example.org
That will make the field into editable field – enter new email that you have access to.
6. Once you have access to the admin email, simply go to /wp-admin of your website, and click Lost your password? link.
Click Get New Password, and you will receive the email with the link to reset it!
I hope this is clear enough tutorial, but if you get stuck, feel free to ask for help in comments section below.