No way to tell without more info...do you have access underneath or would you have to tear the subflooring off? Is the floor wooden with joists, or poured concrete? Which way do the joists run? Which direction do the drain lines run now? WHere is the waste stack? Are you tearing out the wall covering, too? You need to relocate the drains, vents, and water supply lines. It could get quite expensive, and impossible without access from below. Access from below may involve a neighbor, tearing out the ceiling, and redoing that - which you may never get access to or come to an agreement on timing, or price. Some places require the drains to be in cast iron - this will boost the price considerably. So, plan on it being expensive, but you may be pleasantly surprised. You'll want to get at least a couple of quotes, then you'll know. I spent about $1500 relocating a toilet and tub, then replumbing a vanity in a small bath where they had access to the drains (the subflooring was torn off). It could have been a lot more. In NYC, I'd expect it to be more.