Which action can a Declare OnChange rule perform when a specified property changes?

You perform a major skim on the ruleset ABC:02-02 to ABC:03-01.
In the Answer area, select the ruleset versions that the skim operation uses.
Does the skim operation to the ruleset version?

A data page is used to retrieve data from an external system. If an error occurs, you want to display a message to the user and send an email to the system administrator.
How do you implement this requirement?

The AccountManage ruleset contains the following versions of a service level named ReviewAccountChange:

The application is being updated with a new patch version of the AccountManage ruleset. As part of the update, the service level is no longer specialized for AccountOpen ases. In the updated ruleset, the circumstancing in the class group applies to all case types.
Which option do you use to reset the circumstancing for the AccountOpen case type?

As a best practice, in which situation do you use a keyed data page?