Spectator identifying verse Rob changed (8)
I believe the answer is:
observer
'spectator' is the definition.
(I've seen this before)
'verse rob changed' is the wordplay.
'changed' indicates an anagram.
'verse'+'rob'='verserob'
'verserob' with letters rearranged gives 'OBSERVER'.
'identifying' acts as a link.
(Other definitions for observer that I've seen before include "One keeping his eye on" , "Watcher, spectator" , "I notice" , "broadsheet" , "One watching, evaluating" .)