Fervent to agree to change (5)
I believe the answer is:
eager
'fervent' is the definition.
(I've seen this in another clue)
'agree to change' is the wordplay.
'to change' is an anagram indicator.
'agree' is an anagram of 'EAGER'.
'to' is the link.
(Other definitions for eager that I've seen before include "Zealous" , "Full of enthusiasm" , "Sharp" , "Keen - enthusiastic" , "hungry" .)