Help with slow motion and fps problems

Hey all,

I've been asked to edit some footage shot by someone else that seems to have been shot in a way I'm not familiar. Now I shoot primarily on a Canon 70D and @ 24fps. When I decide a shot will be slow motion I switch to 60 fps so it's smoother when I edit in post. Not being an expert this is how I do it. However the footage I have seems to have a timebase of 23.98 or 24 and with a Frame rate set to 60FPS.

As a result everything when played on a video player or in premiere is already in slow motion. Biggest problem is there's a lot of light flickering due to this and if I try to reinterpret the footage it doesn't look quite right. Is there a way to fix/convert these clips to get rid of said flickering or bring them up to regular 24 fps without slow motion? I hope I'm making sense. lol

Thanks!

Jason