(procedure) Select the panorama image layer and execute “VR Comp Editor.jsx” from the Window menu. If a warning appears on the screen, check the “Allow Scripts to Write ...” Preferences. Execute “Add 2D Edit” in VR Comp Editor panel. A camera layer is created in the composition, so change the zoom or rotate the camera to get the desired image.
Another method is to use a plug-in. Although it is Mac only, "dashwood 360 toolbox" can be used for free. Paid plug-ins include RE: VIsion's RE: Lens.