You can define a state in a case type as Transitory if you do not wish the case to exist in a particular state. For example, let's assume that an algorithm is associated with the Decision Checkpoint state (Enter Processing) that would automatically determine the next state for the case (i.e. Cancel/Rebill or Reject ) and also contains logic to transition the case accordingly. In this scenario, you may not ever want the case to exist in the Decision Checkpoint state, so that a user won't ever see a high bill complaint in that state. If the other states were marked as non-transitory, and an error were to occur during the transition from Decision Checkpoint to Cancel/Rebill, the case would roll back any changes to data made in the Cancel/Rebill (Enter Processing) state along with the changes made in the Decision Checkpoint state, and would end up in the Field Investigation In Progress state - the last non-transitory state prior to Decision Checkpoint.