Agent goes to personnel department because editor changed what they'd written (9)
I believe the answer is:
rephrased
'changed what they'd written' is the definition.
I can't judge whether this definition defines the answer.
'agent goes to personnel department because editor' is the wordplay.
'agent' becomes 'rep' (short for representative).
'goes to' is a charade indicator (letters next to each other).
'personnel department' becomes 'HR' (Human Resources).
'because' becomes 'as' (I've seen this in other clues).
'editor' becomes 'ed' (abbreviation).
'rep'+'hr'+'as'+'ed'='REPHRASED'
Can you help me to learn more?
(Other definitions for rephrased that I've seen before include "freshly set down" , "in other words" .)