How to allow the approver to edit the performance ratings given by the line manager

Summary: We have a requirement where Line manager completes the "Manager Evaluation of Employee" task in the performance document and submits it for approval, in our case approver is auditor (AOR) who is kind of a department head, and approver should be able to edit the ratings given by the line manager for calibration purposes. But there is no option available in the approval notification for the approver to edit the ratings in the performance document (Similar to the option in performance goal approval).

Please let us know how to achieve it.