Update end of chapter, altering free and quiet (7)
I believe the answer is:
refresh
'update' is the definition.
(thesaurus)
'end of chapter altering free and quiet' is the wordplay.
'end of' suggests the final letters.
'altering' indicates anagramming the letters.
'and' is a charade indicator (letters next to each other).
'quiet' becomes 'sh'.
The last letter of 'chapter' is 'r'.
'free' anagrammed gives 'efre'.
'r'+'efre'+'sh'='REFRESH'
(Other definitions for refresh that I've seen before include "Enliven once more" , "Revive, cheer" , "Invigorate -- her serf (anag)" , "brace" , "Give drink to" .)