We have already reported on practical use cases for Revit phases here on the blog:
Divide Revit model into construction phases
Phases in Revit
But what do the phases mean for the IFC export and can we export canceled elements? I provide the answers to this question in the current video (see link below) or here as a summary:
Only one phase can be exported from Revit at a time. However, as the phases build on each other, this means that all of the work in the selected phase existing elements can be exported.
The emphasis here is on existing - canceled elements cannot be exported directly, which makes sense in my opinion, as this could lead to confusion. After all, these elements are only displayed in Revit thanks to the filters and such filters do not exist in the IFC schema, but can only be set up in the corresponding IFC viewer.
However, version comparisons can be used very effectively for coordination purposes: for example, it is possible to display all changes between two phases on Autodesk Docs. To do this, the first phase is first exported to IFC and stored on Docs, then the second phase (with the same file name!) and also stored on Docs, whereby the first version is overwritten - however, versioning is also carried out in the background, which enables the version comparison:
Last but not least, it is of course also important to export the information about the phase affiliation of the building components - these are not part of the standard properties and can best be created with the following user-defined property set for all building components:
In the German-speaking Revit:
Phase created = Phase created
Phase demolished = Phase aborted
Click here for the full video (in English):
German 
English