Turn over and turn writer with key (5)
I believe the answer is:
upend
'turn over' is the definition.
(I know that upend is a more specific form of the action the turn over)
'turn writer with key' is the wordplay.
'turn' becomes 'U' (a 'U-turn' is a kind of turn).
'writer with' becomes 'pen' (I've seen this in other clues).
'key' becomes 'd' (musical key).
'u'+'pen'+'d'='UPEND'
'and' is the link.
(Other definitions for upend that I've seen before include "Trip" , "Set on side, turn over" , "make stand" , "Set upside down" , "Stand erect" .)