Make some goal fields non-editable during the evaluation phase

Hi,

in the performance process we manage the goal setting outside the performance document (the employee can propose goals to the manager from the goal page by means of an approval flow).

After the goal entry process, when the evaluation phase starts and the performance documents are created, the goal fields in the document are editable.

We would like to know if, during manager and employee evaluation, there is a possibility in the performance document, not to make all goal fields editable except the "Actual value" field.

The "Actual value" field must be the only editable field for manager and employee.