Objective Setting & Appraisal for Employee in ESS

Hi, I am New in ESS-OSA

I have the following request

In the company want that the employee can appraise to his Manager through of the funcionality of Employee Self-Service.

I am reading in the help.sap and the manager can create appaisal but the employee not.

Someone can help me . How can solve this issue? How can do for that the employee appraise to his/her manager by anonymous ?

Kind Regards,

JuanESS.