Open	Who acts
Country or State → row actions → Slice and Dice	Master maker and reviewer

Apply a corrected value only within part of an approved period while preserving the values before and after it.

Field	Value or selection	Meaning and effect
Original period	The selected approved segment	Choose one current segment, not a superseded historical copy.
Correction start/end	D1 through D2 inside the original period	Inclusive boundaries produce preserved left/right periods when those sides exist.
Changed values	For example a corrected training name	Only the proposed period uses the new values.
Period change reason	The offered period reason plus business explanation	Explains both value and timing changes.

Step	Action	Expected visible result
1	Open a long enough approved segment and select Slice and Dice.	The original values and full period are visible.
2	Set the correction to D1 through D2 and change the intended name/description.	The subperiod differs from the original interval.
3	Select Preview dates and inspect every segment.	For an interior correction, left keeps old values through the day before D1, middle uses new values through D2, right restores old values from the following day.
4	Confirm there are no gaps or overlaps before submitting.	The proposed timeline is continuous where the original was continuous.
5	The reviewer compares the entire treatment and records the decision.	Approval applies the exact previewed treatment.
6	Query an effective date before, inside and after the correction.	Each date resolves the expected segment while earlier recorded versions remain preserved.

Observation	Next action
Preview reports Not a split	Adjust the subperiod or use Edit; a whole-period replacement is not a Slice and Dice demonstration.
A Country reduction conflicts with approved States	Resolve dependent State coverage first; parent inactivation must not leave unsupported active children.

Completion check

Show all three effective-date results and the preserved original representation.

Use date views and preserved versions to explain what applied when and what was known at each recorded time.