Lift to reveal switch (8)
I believe the answer is:
elevator
'lift' is the definition.
('elevator' can be a synonym of 'lift')
'to reveal switch' is the wordplay.
'switch' indicates an anagram.
'to'+'reveal'='toreveal'
'toreveal' anagrammed gives 'ELEVATOR'.
(Other definitions for elevator that I've seen before include "US lift" , "may give you a lift" , "North American lift" , "one that goes up and down" , "A lift in America" .)