There are few ways to change password
Via Wordpress admin panel
If you have access to the admin panel, log in and click on "Update Profile"
Without access to the admin panel
The password-reset page is generally located at:
http://domain.tld/wp-login.php?action=lostpassword
where “domain.tld” is the location of your WordPress installation.
Once you request a new password, an email is sent to the email account with which you registered. In that email is a link to reset your password, which is finally sent back to your email account.
Changing Wordpress password via phpMyadmin
1. Log in your control panel
2. Go to phpMyadmin
3. Browse the database created for your Wordpress and find the “wp_users” table
4. Click on the user you want to edit
5. Go to "user_pass" and under Function chose MD5
6. Enter your new pass and click "Go"
