In our complex we have some townhouses with a concrete tiled patio. We had one owner who proceeded to pull up the tiles and damage the concrete underneath. We wer able to intervene before more damage was done. There is much more to consider than it just being common property. From this experience above we found that there could be implications as this patio was part of the slab of the townhouse. I would ask the OC to provide an engineers report if they insist on removing this patio and not replacing it.
I am with Whale here were I believe that the EC/OC should restore this area to its original condition that is a tiled concrete patio area.