Change of membership upset Liberal in new arrangement, mostly (9)
I believe the answer is:
reshuffle
'change of membership upset liberal' is the definition.
I can't judge whether this definition defines the answer.
'in new arrangement mostly' is the wordplay.
'in new' becomes 'res' (I can't justify this - if you can you should give a lot more credence to this answer).
'arrangement' becomes 'shuffle' (shuffle is a kind of arrangement).
'mostly' means to remove the first letter (r).
'shuffle' with its first letter taken off is 'huffle'.
'res'+'huffle'='RESHUFFLE'
Can you help me to learn more?
(Other definitions for reshuffle that I've seen before include "Cabinet musical chairs" , "PM's cabinet changes" , "Recycle old cabinet" , "Change members of Government" , "Change round of cabinet post holders" .)