The Account Administrator has access to change My Site administrator passwords through the My Account dashboard.  To change a My Site Administrator password follow the steps below:

 Navigate to the My Account dashboard

 Login to the My Account dashboard using your account administrator credentials

 Navigate to the Site Admin tab

 Locate and select the appropriate Site Admin.  This cause an activation panel to appear below the user list

 Select the Reset Password checkbox

 Click Update

 The Site Admin will receive an email containing their new password.  Also, they will be prompted to change their password the first time they attempt to login with the new password.