Revolutionary undertaking, preparation for publishing (9)
I believe the answer is:
redaction
'preparation for publishing' is the definition.
(documents might be redacted before publication)
'revolutionary undertaking' is the wordplay.
'revolutionary' becomes 'red' (red can informally mean communist).
'undertaking' becomes 'action'.
'red'+'action'='REDACTION'
(Other definitions for redaction that I've seen before include "Amended written account" , "text version" , "writing" , "that's needed if text is poor" , "Editing a work" .)