Benefits from rearranging vast agenda (10)
I believe the answer is:
advantages
'benefits' is the definition.
(I've seen this before)
'rearranging vast agenda' is the wordplay.
'rearranging' indicates anagramming the letters (I've seen 'rearranged' mean this).
'vast'+'agenda'='vastagenda'
'vastagenda' with letters rearranged gives 'ADVANTAGES'.
'from' acts as a link.
(Other definitions for advantages that I've seen before include "Benefits" , "profits" , "Gave a stand (anag.)" .)