Hi, I'm in the early planning stages of a bathroom remodel. My house was built in the 1880's is 4 stories tall and has elaborate original plaster detailing, etc. I would like to remodel a bathroom on the third floor (which was remodeled about 20 years ago, so has “modern” plumbing). I'm hoping to accomplish the remodel with minimal demo outside the bathroom itself. The bathroom is 11 x 6 with a tub, pedestal sink and toilet all along one long wall. The waste and vent stacks (which go up to another bathroom on the 4th floor) are at the head of the tub along one of the short walls. My optimal new layout would involve swapping the position of the tub and toilet (putting toilet closest to the stack and tub farthest away, about 10 feet). I plan on replacing all floor tile, but would like to leave as much of the sub floor in place as possible. The waste plumbing is black pipe/no hub variety (not sure of sizes). In general, should I be able to just swap a closet flange for the current tub trap and visa-versa leaving the venting pretty much as is? Or, will I need to re-do all the waste plumbing/venting and demo the entire subfloor and wall? I realize it probably depends on how the current stuff is plumbed, but let’s assume it is up to code. I’m trying to finalize my bathroom layout and the amount of plumbing involved in the swap of fixtures will help me make up mind.