16:9 to 9:16 aspect ratio

Is there really no way to change the aspect ratio of an existing project in Premiere Elements 2019? I want to be able to recreate a project (1920h x 1080v) to be able to show it vertically on mobile phones (i.e. IGTV and TikTok). The aspect ratio setting doesn't seem to allow you to change them. How can it not be part of the program in these days of needing to display content on multiple platforms?!