Victory sign changes (6)
I believe the answer is:
varies
'changes' is the definition.
('vary' can be a synonym of 'change')
'victory sign' is the wordplay.
'victory' becomes 'v'.
'sign' becomes 'Aries' (star sign).
'v'+'aries'='VARIES'
(Other definitions for varies that I've seen before include "Makes or becomes different, changes" , "Differs, changes" , "'Alters, changes (6)'" , "Changes, deviates" , "Tends to change" .)