It'll relay changes word for word (9)
I believe the answer is:
literally
'word for word' is the definition.
(thesaurus)
'it'll relay changes' is the wordplay.
'changes' indicates anagramming the letters.
'itll'+'relay'='itllrelay'
'itllrelay' is an anagram of 'LITERALLY'.
(Other definitions for literally that I've seen before include "According to the letter, exactly" , "Verbatim" , "precisely as written" , "Without exaggeration" , "Actually, really" .)