Many projects, such as renovations, proceed in phases, each representing a distinct time period in the life of the project. Revit tracks the phase in which views or elements are created or demolished.
A phase filter is a rule that you apply to a view to controlling the display of elements based on their phase status: new, existing, demolished, or temporary.

• If Phasing is created in the model, then elements should be filtered by views as different Phases. Use these views to export the Navisworks file. 

In Revit users can develop, evaluate, and redesign building components and rooms within a single project file by using the 'Design Option' feature. 

• Design Options should be reviewed and if available, create different views and export.