Changing a MySQL user’s password is a task handled by the database administrator (root).
Once the MySQL user’s password is changed, you should update the user’s privileges.
Step 1: Log into MySQL server as root
$ mysql -u root -p
Step 2: Use ‘mysql’ database
mysql> use mysql;
Step 3: Change password for user John
mysql> update user set password=PASSWORD('NEW-PASSWORD-HERE') where User='John';
Step 4: Reload privileges
mysql> flush privileges;