- There are some downgrade rights reserved for Volume License and Software Assurance customers. With that said, these customers can go all the way back to Office 07 Pro Plus or Standard. There are no downgrade rights for end-user consumers (OEM, PKC and FPP do NOT offer downgrade rights), you can probably still find Office 2010 from Amazon or the like though, uninstall Office 2013 and install Office 2010.
- You might like to check Microsoft Install or remove individual Office programs and components to uninstall a particular feature and install the other feature separately, I wonder that might work.
Sources:
- More info: Downgrade rights info from MS - "The OEM License Terms for OEM versions of application software do not grant downgrade rights."
- Related info from Dell.