Free up space in crossdevice mobile phone folder

I like the idea of having my connected mobile device storeg folder accessible from my PC.

It is a very similar concept to OneDrive where you can see the contents/thumbnails of the cloud folders and files, without it actually taking up space on local hard drive. And you can access those when online, by downloading/storing it locally first.

In OneDrive you can free up space by right clicking on the files/folders and free up disk space.

However, I don't see this option for the phone storage files and folders. Why? Isn't there any?

How do I free up local disk space once I don't need to have files/folders stored locally anymore in phone storage? I don't see any option for it by right clicking.

Is there another way? 

Sure, I can delete it, but then it gets deleted both locally and on the phone ... and I just want to free up space on local drive, sort of de-synchronize it.

How?