I have a 2 inch drain pipe coming from an upstairs bathroom through a wall below, I want to expand a window in that area. My question is, can I move the drain pipe 4 feet to the left in the wall with 90 degree elbows and reconnect. The piping is pvc. Thanks, Ken

Yes, you can.

Since you say this is coming from a bath I'm guessing it is actually a vent from another drain. 2" doesn't sound like a toilet/sink drain. Does this pipe lead toward a kitchen or other bathroom? In any case you should be OK making your cuts.