Moving walls/ floorplans

I drew a den, but I needed to move it to the right side of the floor plan I had already created for the rest of the house. Unfortunately, I couldn’t do that. I was told I would have to delete it and start from scratch!

How is something as basic as moving walls, repositioning a floor plan, or even centering the floor plan within the workspace not an option? These seem like fundamental features that should be available.