Return roster to dog warden (7)
I believe the answer is:
curator
'warden' is the definition.
(thesaurus)
'return roster to dog' is the wordplay.
'return' says the letters should be written backwards.
'roster' becomes 'rota' (rota is a kind of roster).
'to' says to put letters next to each other (I've seen this in other clues).
'dog' becomes 'cur' (I've seen this before).
'rota' back-to-front is 'ator'.
'ator' put after 'cur' is 'CURATOR'.
(Other definitions for curator that I've seen before include "Museum custodian" , "Custodian of a collection" , "Museum's administrative head" , "Cultural employee" , "Artistic director" .)