How to update Date Start and Date End on VK12 using FM

Gurus, I'm currently updating data on VK12 using FM RV_CONDITION_COPY.

The program is designed to add or change records. I am not encountering any errors when adding records. The problem is when changing the record. I can only update the price, but not the Date Start and Date End.

I tried using RV_CONDITION_FIELD_CHANGE but to no avail.

Can someone shed some light on this?

Thanks in advance.