To edit an existing Business Rule, navigate to the Rules list view within the Control Panel and click on Business Rules.
Click on the pencil icon at the end of the Rule or on the Rule which is to be edited.
This will take you to the Edit rule page which has the same fields available as the page where the rule was originally defined. The Primary module and Event fields are greyed out as neither can be edited. The Action section will show a cancel icon next to it as only one Action can be applied per rule and the Action cannot be edited. All others fields on the screen can be updated.
To leave the Rule unchanged and instead create a new rule, click on Add Rule from within the Edit Rule page.
To delete a Rule, simply click on the trash icon within the list view.