Changing Wall Lengths of a Room rather than delete entire room.

Hello,

I have created a floor and within that floor have a large number of rooms with a lot of windows, doors, exposed walls and partitions. I have imported a new DXF file and the layout has changed very slightly. Rather than delete entire rooms is there anyway of editing wall lengths once the room has been closed so as to save me having to draw the room out from scratch again?

Thanks

Matt