When editing a break event (execution-related) you have set, first open the Events panel by selecting [View] menu >> [Event]. After selecting the break event (execution-related) displayed in the detailed information on the combination break in the Events panel, click [Edit Condition...] on the context menu. This will open a dialog box in which you can edit the selected break event. For details on editing in the dialog box, see "2.17.4.1 Editing execution-related events".