User Help > Grouping Files Under Version Control > Dropping a Configuration Management Subproject
  
Dropping a Configuration Management Subproject
CLI EQUIVALENT 
si dropproject
* 
Before dropping a subproject, it is a good idea to create a checkpoint. By doing this, you preserve all of the members of the subproject in case it needs to be added again in the future. For more information, see Checkpointing a Configuration Management Project.
If a subproject has outlived its usefulness or just does not belong in a project anymore, you can remove it at any time.
To drop a subproject, select one or more subprojects to remove and select Project > Subproject > Drop.
After you remove a subproject from a project, it is no longer listed as part of the Sandbox or master project, but the subproject’s history remains in the project record, in case you need to recreate an earlier version of the project.
* 
When you remove a subproject, you also remove all members within that subproject.