IBM Connections Blog recommend API

I am working on Blog APIs of IBM connections 3.0 From IBM Docs I got details about how I can recommend a blog entry and how I can get list of peoples recommended blog entry.
I Need details, how I can undo my recommendation for particular blog.
In web IBM connections is calling /blogs/roller-services/json for the this action which requires "dangerousurlnonce" to be posted, I could not find, how I can get the value for "dangerousurlnonce" either.
-- Priyanka