Overturn northern result (5)
I believe the answer is:
upend
'overturn' is the definition.
(I've seen this before)
'northern result' is the wordplay.
'northern' becomes 'up' (eg in the term 'upstate').
'result' becomes 'end' (I've seen this before).
'up'+'end'='UPEND'
(Other definitions for upend that I've seen before include "Turn on its head" , "Flip" , "Put into disarray" , "Alter greatly" , "change things drastically" .)