Locate the ruleset (Where is my ruleset?), expand the ruleset node, the Decision Tables folder and in the context menu of the decision table node choose Rename.

or

Locate the flow ruleset (Where is my flow ruleset?) , expand the flow ruleset node, the Decision Tables folder and in the context menu of the decision table node choose Rename.

In the dialog box that appears, the existing name of the decision table appears in the field. Enter the new name for the decision table in the field. Choose OK.