Rotate landscape video to portrait for upload to IGTV

Hi,

I create videos for my YouTube channel in landscape mode. I would like to use those same videos to upload to IGTV. The requirement is that they have to be in portrait mode. I have searched and searched how to change the orientation from 16:9 to 9:16 but can't find it anywhere (and where I found the orientation, it wouldn't let me change it).  I have changed the video clip to be oriented sideways, but the doesn't resolve the issue that the format is still 16:9 and not 9:16.

Does Premier Elements 2018 (v. 16) offer the ability to change the orientation? If so, how do I do that? Thanks!