Plumbing and Piping - Question about removing small shower

Let me see if I can Explain myself. First I have a second bath, which has a small 3x3 shower and right beside it there is a cabinet, 2' wide to the ceiling, which is a towel cabinet. Now what I am going to do is tear out the cabinet remove shower stall. That will give me a 5'x3' open spot. Now since the shower has a cast iron drain in center. I need to know what or how could this be change over to accept a drain only for a Washer. My plan is in this area frame it in on the bath side and open it up on the other side and put my washer and dryer in this area. So now as far as the center drain I know it will have to be routed back a little to get it by the wall so the washer will fit, and put the drain by the wall. What kind of plumbing changes do I need to doget this to work. I hope this makes since. After I get answers on this I will ask the next questions. O by the way I have a slab foundation on my 1963 home in Dallas, just FYI

Sorry no one answered yet.

This is a big job for DIY. Under the shower drain is the p-trap. This cannot be left there. You need to get into the floor ( jackhammer if is is concrete) and move that pipe so that it comes up in or near the wall. A p-trap is installed abouv the floor level, and a standpipe installed for the washer. Connected to that drain is a vent pipe, probably rising in the wall. The $64 dollar question is "which wall". Only when you get into the wall or into the floor will you know the layout of the drain and the vent.

When you start getting things open, post some picture via photobucket.com or otherwise. Then we can further advise.