I suppose you mean employment start and end date.
Tried the following in Dynamics AX 2012 CU2 -
- Terminated an employee.
- In the employment history tab under past workers list page, was still able to view history (i.e. employee start and end date).
The actual dates are stored in ‘HcmEmployment’ table and I can’t see any parameter for deleting the dates either. Perhaps do you have any customization around this area?