How do I replace clips in iMovie?

Hello,

I have a movie in iMovie on my iPhone, and I have edited my current clips to look almost the way I want them. However, I can't find a way to replace them with clips from Photos (I'm trying to replace the same clips [to avoid re-editing], and the difference is that the versions in Photos are tilted to look better and the ones in iMovie aren't tilted). Is there a way to replace clips or tilt clips (tilt, like how you can edit a photo or video in Photos) without having to re-do my editing? I am looking for a way that would work on my iPhone, because I don't have a Mac or iPad. If there is a way on a Mac or iPad, please let me know, but I would prefer an iPhone way so I don't have to borrow someone else's device.

Thank you.

Alexandra