Please review the white papers posted at www.autodesk.com/greenbuildingstudio-features for more information.
Currently you cannot change the number of people, unless you want to edit the gbXML file and resumbit it to Green Building Studio. The occupancy is assigned based upon building type using ASHRAE baselines.
Keep in mind that Green Building Studio is meant for early schematic design decision-making. More detailed engineering analysis can be performed by exporting the DOE-2 file or the EnergyPlus file from Green Building Studio and used in eQUEST or EnergyPlus.
Autodesk Green Building Studio Product Manager
Marjorie Stein QA Analyst Green Building Studio Autodesk, Inc. firstname.lastname@example.org
One other enhancement re: changing people and other defaults. You can define your own templates in Green Building Studio. That allows you to set defaults that are more appropriate to your project if you have enough information or want to change assumptions.
From the my projects screen, choose "Create Project Templates" and you can modify many different items.