Beg for change in net rate (7)
I believe the answer is:
entreat
'beg' is the definition.
(to entreat someone is to beg or plead)
'change in net rate' is the wordplay.
'change in' indicates anagramming the letters.
'net'+'rate'='netrate'
'netrate' is an anagram of 'ENTREAT'.
'for' acts as a link.
(Other definitions for entreat that I've seen before include "Pray" , "Sue" , "Beg earnestly, implore" , "Ask (someone) anxiously" , "Beseech, implore" .)