DUP unsettled: worried in reform (6)
I believe the answer is:
update
'reform' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Perhaps you can see an association between them that I don't see?
'dup unsettled worried' is the wordplay.
'unsettled' indicates anagramming the letters.
'worried' becomes 'ate' (something worrying may eat someone up).
'dup' with letters rearranged gives 'upd'.
'upd'+'ate'='UPDATE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for update that I've seen before include "Modernise, modify" , "Later information" , "Revise to include latest developments" , "account of the latest developments" , "Bring to present status, say accounts" .)