how can I delete dropbox files only (!) on my ipad?

I have my ipad connected to my Dropbox. everything works fine.

I can download a file to make it available offline when I press the little cloud with the error on the right side of the name. how can I delete this local copy? (such that it is not deleted from my dropbox, but it does not take up any space on my ipad anymore)

Thanks for the answer

O