Admins can allow managers and department leaders to launch reviews of their own. Reviews they launch will only be for their direct reports --in the case of Managers, and/or departments --in the case of Department Leaders.
To find the ON/OFF toggle switch for this go to Settings>Reviews
A manager or department leader can then:
Launch a new review for employees in their reporting tree or employees in departments they lead
Add additional participants to that review once it's launched (from the Progress and results tab), from their reporting tree or department
See reviews on the 'Manage review groups' tab for reviews they have launched, not ones launched by other people or Admins
Delete a review they have launched
At this time Admins or other Review creators will not be able to see draft reviews created by others, only the creators of a review in draft mode can edit it.
When a review is launched then Admins can see its contents, depending on their level of content access, via the Progress & Results page, and can add participants or move the reviews forwards or backwards.