While the phasing tools in Revit are pretty useful, it is unfortunately not possible to demo part of a Curtain Wall. The phasing parameters can only apply to the overall Wall object, not the Mullions, or Panels or Grids.So what to do? Well cheat of course!What you need to do is create the Curtain Wall in pieces. Since you cannot add phasing to a portion of the overall Curtain Wall, make several smaller Curtain Walls based on what phase they need to be. It is more work admittedly, but it does do the trick.The basic process is as follows.

• Revit Delete Curtain Wall Grid

Look for where you can break up the Curtain Wall. Don't simply use the split tool in plan, because this will split the Curtain Wall along its full height. Rather, use the Add/Remove Grid segments command and the Empty System Panel to remove just the portions you need to remove.

Then go back and draw new small Curtain Walls in the locations that you removed from the main ones. These smaller Curtain Walls can then be assigned any phase as needed.It is very important to use the System Panel: Empty panel type where you want to 'delete' panels. Do not simply try to delete them. This does not work.

Revit will keep adding a default panel back again after you delete. Use the Empty panel and it will appear like it has been removed.I have prepared a short video of the steps. You can watch it.

Revit Delete Curtain Wall Grid

While the phasing tools in Revit are pretty useful, it is unfortunately not possible to demo part of a Curtain Wall. The phasing parameters can only apply to the overall Wall object, not the Mullions, or Panels or Grids. If the curtain system has the grid layout hardcoded in the type parameters you will not be able to delete those grids. Any grids that are placed manually (by choosing 'none' for the layout) will be able to be deleted. Remember that it is possible to have manually placed and hard coded grid layouts in the same curtain system. Hope this helps.