Ring to check about transport going to West Ham (7)
I believe the answer is:
overact
'ham' is the definition.
(ham can mean to overact)
I cannot understand how the rest of the clue works.
(Other definitions for overact that I've seen before include "Ham (on stage)" , "Play (part) in an exaggerated manner" , "Cartoon twenty four across" , "Exaggerate" , "Be excessive like fulsome thespian" .)