Removing a Condition in a Decision Table 
In the Rules Navigator view, expand the project node and select the ruleset or flow ruleset.
The ruleset or flow ruleset overview page opens in the Editor Window.
Under the Decision Tables section, select the decision table and choose Open.
The decision table opens in the Editor Window.
Choose Condition.
In the Remove Conditions dialog box that appears, select the conditions you want to remove and choose Ok.