Click on "My Accounts" and select "View" on the Account which you wish to have the password reset. 

Click on "Actions". 

Click on "Change Password" and that will automatically change it for you.

Once that has been done, You will need to copy the password and put it somewhere safe.

Please note: If you click change password, don't copy the password beforehand and click somewhere else you will need to do it again because your password would have been amended and your old one would not work anymore.