After a review cycle has begun and the peer selection phase has ended, admins (or users assigned a custom role to create the review cycle) can remove peer reviewers for all reviewees.
Note: If the peer reviewer has already submitted their review, it will be permanently deleted upon their removal.
Navigate to Admin > Performance > Reviews.
Select the review cycle.
In the Reviews phase, select the Reviewees tab.
Find and select the reviewee you would like to remove a peer reviewer from.
A context panel will appear –– Next to Peer Reviewers, click Edit.
Select the X next to the peer reviewer's name.
Confirm to remove this reviewer.