Resignation - Resignation date should be derived automatically when we are notification Date is defa

Organization Name (Required - If you are an Oracle Partner, please provide the organization you are logging the idea on behalf of):

Sierra Cedar India

Description (Required):

We are defaulting the notification date to system date but when we do that resignation date is not auto-derived. But when we go ahead and change the notification date - it does gets derived.

Our clients did not wanted the employees to change the notification date and hence we need to default it to system date and make it read only.

Use Case and Business Need (Required):

Resignation date should be auto derived when the notification date is defaulted.