To update your Quantum Core client area password please follow the following steps:
1) Login to the Quantum Core Client area HERE
2) Once logged in, hover your mouse on "My Account" located at the very top of the page and click on "Edit Details" (alternatively, click HERE)
3) Select "Change Password" from the left hand side
4) Enter your existing password and then your new password and click "Save Changes"
5) Your new password will be set immediately