The exception helps us notify the though which the natural condition or flow on order is interrupted. There can be a condition that requires a comparison of various calculated fields, dates, and quantity based on the input user. Such as check if the actual margin for customer /product is less than a certain value, or the delivery date is not confirmed with two business days for an order from the date when the order is placed or else the quantity delivered is less than confirmed quantity.

This can be achieved with the help of the custom function. Functions are provided by the developer and are available for use in the Group Function tab under the Exception Builder.