I am remodeling my main floor bathroom and need to reposition the sink by about 1 foot. There is also another bathroom directly underneath in my basement. What do I need to do to make this happen easily?

Thanks.

If you are only moving 1 ft you probably will be OK with the existing set up, just add a longer P trap pipe. Are your supply pipes rigid copper or flex pipes? If they are flex you can just buy longer ones.

The house was built in 1954 I believe it's galvanized steel, there's no copper showing. The vent appears to be cast iron. Also, the sink is on the opposite side of the room from both the toilet and tub.

But you are only moving 1 ft to the side, right? They supply pipes come out of the wall or the floor. They should have a shut off called a stop cock. You can attach flex pipes at the stop cock that will run up to your sink. I'm picturing this will lokk OK if the lav sits on a cabinet. If the sink stands alone you can still do what I'm saying but it may show and look a bit odd.

When you touch old galvanized piping you are begging for problems. The cast iron possibly has lead arms to the lavatory. All the work can be done in the wall but you best pay a plumber to do it to limit your liability.