Scheduling a case task can be done manual or automatic. The Organization Option CASECASC will calculate scheduled dates for case tasks automatically based on the previous tasks and the task duration.
If the option is set to SCHED, then the system will automatically calculate scheduled start and end dates for a task if changes are made that would affect those dates, like a new task is inserted, an existing task is deleted, moved to another sequence, or simply because you changed the start date or duration of a task.
If the option is set to BOTH, then the system will updated scheduled dates like described above, but will also update requested start and end date, but only if a date was entered and that date conflicts with the scheduled date. For example if the scheduled end has been recalculated and the requested end is set to an earlier date, then the system will set the requested date equal to scheduled end. If requested end was already set to a later date, then the system does not see that as a problem and will not change requested end.
If the option is set to NO, then the system does not do any calculation and will not automatically change the scheduled start and end dates.