A starter bound not to get on (3)
I believe the answer is:
bud
'get on' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
'a starter bound not' is the wordplay.
'a starter' says to take the initial letters.
'not' becomes 'ud' (I am not sure about this - if you are sure you should believe this answer much more).
The initial letter of 'bound' is 'b'.
'b'+'ud'='BUD'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for bud that I've seen before include "Tight flower" , "Small knob that will develop into a leaf or flower" , "mate in America" , "American beer" , "Undeveloped flower" .)