Using this feature you can update a judge's evaluation form answers or rank position choices quickly without needing to impersonate the judge.
In Judging > Status by Submission click on the number of assignments in the Assigned or Complete columns and then click Edit Scorecard.
You will be taken you to the judge's view of that submission and will be able to update their evaluation form questions or rank position choices.
This feature is also accessible in Judging > View / Add Judges.