Save edits directly over someone else's workspace project?

Hi,

I'm collaborating on creating a report in Analysis Workspace with another member of my team.  He is the designated "owner" of the project but has shared the report project with me.  However, after making edits on his report, I can't seem to save directly over this file (it only provides the option to "Save As" a new project).   Does anyone know if it's possible to save over the original file? (or if there are specific permissions that need to be granted first)?

Thanks!