Portrait camera angle

Hi all, Im aware that you cannot change the angle of the camera to portrait just on one scene so can anyone thing of a way I can zoom in on a video that is showing how to reset your password using the mobile app. I have been given the video so it is showing in a portrait format so the phone mask needs to be upright instead of side ways so I was just wondering if there is a way to zoom in on it at all.

Hope this makes sense and any help/advice will be greatly appreciated.