It's frowned upon to back out of an agreement.
Robert just agreed with his regular plumber about a big repair job at his house when he discovers that another plumber would charge him less.
Robert wants to save money.
Robert discusses the situation with his regular plumber, and they agree on a lower price.
Robert cancels the job with his regular plumber without explanation and hires the less expensive one instead.
Robert's regular plumber's schedule goes as planned and his employees work their regular hours.
Robert's regular plumber has to reorganize his schedule and decrease some of his employees' hours.