If you have to have a manager re-do their review of team members you can un-submit the reviews. This will allow them to re-visit their answers and make any changes necessary with the new information you provide.
You can do this by going to the reporting overview for the cycle.
Once in the reporting overview, you can select a number of employees whose manager reviews have to be changed. The unsubmit review button will appear in the top right corner.
From here, you can select the Manager Review as the review you wish to unsubmit and add a comment to the managers, clearing up any issues they might have had that meant they had to re-do their reviews.
They will receive an email letting them know that their review was unsubmitted, and your comment will be in the email.
If the manager had shared the review with their employee, the employee will get an email letting them know they can no longer see that review until the manager has completed it and shared it with them again.