The following info came from the SBS Product team on the best way to change the password on the Administrator account:
To change the password, however, you can use any of the methods that any user would use to change their own password, plus some others. For example:
1. When logged in as Administrator, press Ctrl-Alt-Del, click the “Change > Password” button, and change the password.
— or —
2. Open Active Directory Users and Computers, find the Administrator object, right-click on it and select “Reset Password.”
Note that option 1 is preferred, as option 2 forces the password to be reset, which can cause the account to lose access to encrypted files and potentially other data.
SBS Product Team