Let it change name (5)
I believe the answer is:
title
'name' is the definition.
(eg the name of a book)
'let it change' is the wordplay.
'change' indicates anagramming the letters.
'let'+'it'='letit'
'letit' with letters rearranged gives 'TITLE'.
(Other definitions for title that I've seen before include "Form of address - name" , "Name of book or lord" , "'The name of a book, say (5)'" , "inscription" , "Rank < deed" .)