In a lucid dream, you "consciously" change things. For example: In one dream I had, I was skiing down the hill, and as I got closer to the bottom, the snow got more and more melted, exposing dirt and rocks. I realized I was dreaming, and thought, "I can fix this!" so I made a wide swath of fresh, soft powder in front of me as I continued to the bottom.
Erin describes that as she got better at lucid dreaming, she was not only able to alter things within a dream scene, but able to change dream scenes, often choosing to be a superhero or visit attractive celebrities. (I believe she said this on a
podcast she recorded