Copy Mask suggestion

Not sure if this is possible, but making a copy of a mask could be useful in some situations.
EG. A foreground object is masked and adjustments made. You then want to make different adjustments to the remainder of the image and therefore need an inverted copy of the mask.
Terry
EG. A foreground object is masked and adjustments made. You then want to make different adjustments to the remainder of the image and therefore need an inverted copy of the mask.
Terry