Screw around and do sketch again? (6)
I believe the answer is:
redraw
'do sketch again?' is the definition.
'screw around' is the wordplay.
'screw' becomes 'warder' ('screw' is an informal term for a prison warder).
'around' shows that the letters should be reversed in order.
'warder' backwards is 'REDRAW'.
'and' acts as a link.
(Other definitions for redraw that I've seen before include "Find a new winner" , "Sketch again" , "Change" , "Pick over" , "plan afresh" .)