In order to change the evaluator for an assignment, you can:
Click on “Courses” and
Select “Batches”
Filter for the course and select the batch for which the evaluator is to be changed.
Click on the “Assessments”.
Click on the drop-down indicated by the three dots
Select “Change Evaluator”
Select evaluator from the drop-down.
Save
The evaluator for the assignment is now changed.