changing video to landscape

[right to carry]

I started several video (accidentally) in portrait mode, then held my phone in landscape mode thinking thats how it was recording. When I downloaded them and viewed them on my laptop, I have to turn the damn laptop to see them in landscape. Is there an editor app or something in my S9+ that can rotate the view and save it permanently in landscape mode. Yes I am challenged and need help... thanks

 

[SpookDroid]

the included video editor should have a rotate button (if your phone doesn't have it, you can install it from the Galaxy Store).