When you demo an existing door or window in an existing wall in the New Construction phase Revit automatically places an infill wall into the New Construction phase to replace the door or window that was demo'd. I've run into a number of projects where I wanted to demo the door but leave the opening. Here is an interesting solution.
All you have to do is add a comment to the instance properties of the infill wall like "Opening." Then filter walls by the comment "Opening" and hide those walls in all of your views.