Edit only the actual value for a Goal

Summary

Is it possible to set only the actual value not in read only for a Goal

Content

Hello,

we are trying to manage a requirement with a client in order to have the possibility to edit only the field of the actual value of the Goal.

In details into a Performance Document in the section Goals we need that only the manager can edit the actual value of the goal. What we would like to have is that when the manager click on the goal, entering in the details of goal, he can only edit the field "Actual value" while all the other field are in read only.