Free from fault (5)
I believe the answer is:
emend
'free from fault' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Perhaps there's an association between them I don't understand?
This is the entire clue.
Can you help me to learn more?
(Other definitions for emend that I've seen before include "get rid of faults" , "do editorial work" , "would appear better" , "Improve by altering" , "Alter to improve (text)" .)