This function is found under Settings>Manage Rules.
Reorder the Rules List
To change the ordering of individual items in the rules listing, simply click on an order line item and then drag-and-drop it to the location that you want it to occupy in the listing. Your rules currently fire in chronological order. This order can be adjusted.
NOTE: If an order is flagged by conflicting rules the most negative rule will win. For example a single order gets a rule that sends the order to a work queue and a different rule that flags the order to be auto-cancelled, the order will be auto-cancelled.