A bit of a silly question, and I've searched but haven't found a simple answer.

Basic problem: I've drawn a desk for an IT position, and it's slightly recessed where the chair is so the desk "wraps around" the person to a degree.

I've drawn this with straight lines, effectively having a /----\ kind of shape - see below. Question is, how can I smooth those angles into curves? Can it be done without redrawing the desk from scratch?