Step::1 Login to your client area.
Step::2 Click on Services.
Step::3 Now click on the green colour Active button.
Step::4 Now on the next page on the right hand side find change cpanel password option and click on it.
Step::5 Now here in this page fill the old password and new password and click on save new password.
That's It !
Check out the video tutorial to know the procedure in detail. You may refer to the blog as well.