How to remove reflections from images?
I am not a specialist in image processing but I highly doubt this is feasible with your requirements (single image, no prior information). The challenges is twofold:


Detect which area of the image is a reflection. This looks like a quite complex scene understanding problem. In your example, I know that the right side is a reflection because I can infer from the image that a person is depicted here, and I have prior knowledge about what the back of a person looks like.
Reconstruct the background in the identified region. While it would be possible to just inpaint the area detected as a reflection with textures from the surrounding, the result would hide many details! Whatever I've seen in the field of single input image separation was relying on very simple image models (stationary textures), not real world images. The more traditional image separation setups (multiple channels, recto/verso of translucent pages, multiple polarization) do not apply to your case.