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 'Info' screen pops up, click the grey 'x' icon next to the name of the person you want to remove.
2. On the review screen, click on the reviewer’s profile picture on the right-hand side of the frame. Then click the ‘remove’ button.