Adding a Precondition 
In the rule editor you can set rules as preconditions to another rule. When you set a precondition, the existing rule gets fired only when the precondition is satisfied.
Procedure
Locate the ruleset, expand the ruleset node, the Rules folder and double-click a rule node.
For more information, see Locating the Ruleset
or
Locate the flow ruleset , expand the flow ruleset node, the Rules folder and double-click a rule node.
For more information, see Locating the Flow Ruleset
NoteYou can also expand the Rules folder in the Outline view and choose a rule node.
End of the note.In the rule editor that appears, under the Preconditions section, choose
(add a new Precondition) and choose a rule
in the drop down menu.By default the rule is set to must be satisfied. You can change it to must not be satisfied by clicking it.
Save the changes.
NoteTo delete a precondition:
In the rule editor that appears, under the Preconditions section, select the preconditions you want to delete and press Ctrl + D.
In the dialog box that appears, select the preconditions you want to remove and choose OK.
You can choose the Select All and Deselect All buttons to select or deselect all the conditions all at once.
End of the note.