Log into your cPanel administrator and look for the Change Password icon. Click that button, you will need to enter your existing or current password before entering your new password and then again to confirm it.
Watch this tutorial to see how to accomplish this task: Changing your access password
There is a way to reset your password from the front-end, you will need to use this URL (http://www.yourdomain.com/login/index.php?option=com_registration&task=lostPassword) and must know your username and email address your account is registered under.
Enter the information and click the Send Password button. You will receive and email with instructions on recovering your password.