Managed to uncover Sinatra? (3)
I believe the answer is:
ran
'managed' is the definition.
(I've seen this before)
'to uncover sinatra?' is the wordplay.
'to uncover' means to look at the middle letters (the outer letters are uncovered).
'sinatra?' becomes 'Frank' (singer Frank Sinatra).
The middle letters of 'frank' are 'RAN'.
(Other definitions for ran that I've seen before include "Was a scooter" , "Moved fast or managed" , "Entered an election or managed" , "Was candidate" , "was in charge" .)