Yes, provided they’re not a team member. There are two ways to do this:
1. On the projects screen, click the green info ‘i’ button on the thumbnail. Then when the 'Video info' screen pops up, click the grey 'x' icon next to the name of the person you want to remove.
2. On the video review screen, click on the reviewer’s profile picture on the left-hand side of the video frame. Then click the ‘remove’ button.