Magi set out with tree's leaves (9)
I believe the answer is:
emigrates
'leaves' is the definition.
The answer and definition can be both related to change as well as being verbs in their -s form.
Perhaps there's a link between them I don't understand?
'magi set out with tree's' is the wordplay.
'set out with' indicates an anagram.
'magi' anagrammed with 'trees' makes 'EMIGRATES'.
Can you help me to learn more?
(Other definitions for emigrates that I've seen before include "Goes to another country to live" , "Goes abroad to live" , "seeks new home?" .)