One who may turn out a successful actor (7)
I believe the answer is:
dresser
'one who' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'turn out a successful actor' is the wordplay.
I cannot really see how this works, but
'turn' could be 'dress' (dressing is a kind of turning) and 'dress' is located in the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'may' is the link.
Can you help me to learn more?
(Other definitions for dresser that I've seen before include "Item of furniture - actor's assistant" , "Wardrobe assistant" , "One covering up" , "Person working in one theatre" , "Sideboard - backstage assistant" .)