Collaborative review and feedback is an important part of conventional filmmaking and now Virtual Reality (VR) video production as well. However, conventional collaborative review practices do not easily translate to VR video because VR video is normally viewed in a headset, which makes it difficult to align gaze, share context, and take notes. This paper presents CollaVR, an application that enables multiple users to review a VR video together while wearing headsets. We interviewed VR video professionals to distill key considerations in reviewing VR video. Based on these insights, we developed a set of networked tools that enable filmmakers to collaborate and review video in real-time. We conducted a preliminary expert study to solicit feedback from VR video professionals about our system and assess their usage of the system with and without collaboration features.