When you have chosen for managers to go last, your goal is for all reviews to be submitted before the manager writes and finalizes their manager review. However, there will likely be times where a slow reviewer is holding up the manager. In those situations, admins have the ability to "unlock" the manager review for a employee or all employees. To do this:
Step 1: Navigate to the "Admin" panel found in the top navigation bar
Step 2: Click on "Reviews" found in the left Administration panel
Step 3: Find the appropriate review cycle and click "Manage cycle" to the right
Step 4: From here, find the reviewee's name whose manager needs to submit their review and click on the ellipses next to the reviewee's name
This will email the manager and allow them to submit their review.
Additionally, if you have a group of managers who need to submit their reviews, you can click on "Unlock manager reviews".
Note: this does not lock out the other reviewers that have not submitted their reviews yet. This just gives managers the ability to submit their reviews right away.