Woman in diocese undergoing change of heart (3)
I believe the answer is:
sue
'woman' is the definition.
(woman's name)
I cannot understand how the rest of the clue works.
(Other definitions for sue that I've seen before include "Proceed legally against (someone)" , "Make a case against" , "Take case against in court" , "Bring a legal action" , "Begin legal proceedings against" .)