Hi there,
it would be groundbreaking feature to develop feature that allows to swap texture after image was rendered. There is Colimo (Motiva) software but somehow abandoned. I saw few requests years ago but nothing happened in that area.
Imagine that CG artist is able to swap textures and make tens or hundreds variations in no-time just to show his customer many options for him to choose from between. Or better yet - a packshot of a single furniture with hundreds of combinations (body, legs, cushions, etc.). Something tells me that its achievable just with render elements.
Cheers!