Deleting a Decision Table 
You can permanently remove a Decision Table from the rules composer DC. You cannot delete a decision table if it is being used in an If-Then rule.
Locate the ruleset (Where is my ruleset?) and double-click the ruleset node.
In the Outline view, in the context menu of the Decision Table node, choose Delete.
In the dialog box that appears, choose Yes.
Note
If the decision table you are deleting is being displayed in the editor, then after the delete operation is over, the next available decision table is displayed. If there are no other decision tables, the Decision Table Editor displays nothing.