What managed to melt? (4)
I believe the answer is:
thaw
'melt?' is the definition.
('thaw' can be a synonym of 'melt')
'what managed' is the wordplay.
'managed' is an anagram indicator.
'what' anagrammed gives 'THAW'.
'to' acts as a link.
(Other definitions for thaw that I've seen before include "following 28 [SILVER]" , "Player of detective" , "get warmer" , "(Of ice/snow) melt" , "Frost going" .)