A reviewer can begin reviewing a document while a translator is working. You can open the Review mode by selecting Review in the drop-down menu next to the document name in your project or - if you are assigned as a reviewer - by just clicking on the document name. As a PM you can assign a separate reviewer from the Share menu or access the Review mode from the document menu.
The reviewer interface is the same Editor that is used for translation and you have access to all of its features. You may find our QA features useful when reviewing. Press Accept on each segment to mark it as reviewed and lock the segment from further changes by the translator:
You can also accept all segments at once by clicking on the check mark next to Accept all confirmed segments on page on top of the page.