Want to stand in centre of Arsenal flag (7)
I believe the answer is:
slacken
'centre of arsenal flag' is the definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Perhaps there's a link between them I don't understand?
'want to stand in' is the wordplay.
'want' becomes 'lack' (synonyms).
'to stand' becomes 'sen' (I can't justify this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'lack' going into 'sen' is 'SLACKEN'.
Can you help me to learn more?
(Other definitions for slacken that I've seen before include "Ease off (work)" , "Loosen -- become less busy" , "reduce tension" , "Loosen, eg, a rope" , "Make looser" .)