I am remodeling a previously tiled shower and replacing with a prefab composite shower floor. The existing drain appears to be cemented into the slab. Will I have to break the slab and remove the existing drain or is there a "magic" adapter that I can use to extend the PVC in order to connect it to the new drain? I suspect I have already answered my question and I need to break the slab, cut the old PVC and glue a new 2 inch PVC extension to the old? Thanks