Revised tale with a revolutionary ending (7)
I believe the answer is:
altered
'revised' is the definition.
(similar in meaning)
'tale with a revolutionary ending' is the wordplay.
'tale with' becomes 'alte' (I am not sure about this - if you are sure you should believe this answer much more).
'a revolutionary' becomes 'red' (red can informally mean a communist).
'ending' means one lot of letters go next to another.
'alte'+'red'='ALTERED'
(Other definitions for altered that I've seen before include "Treadle (anag)" , "Reformed" , "Metamorphosed" , "Changed, modified" , "Different" .)