Yes Movie Studio 13 platinum can do this.
I'd follow steps something like this:
- In Advanced mode
- Begin a new project
- Change the project settings, revising Stereoscopic 3D mode on the Video tab to be "Left only" (or "Right only")
- Add your 3D video to the project
- Revise the video's properties, Media tab, setting Stereoscopic 3D mode to side-by-side (full), or side-by-side (half), so it matches the format of the 3D video.
With this setup, when you render the project you'll get a 2D version of the 3D video.