When cold finish move up (6)
I believe the answer is:
ascend
'move up' is the definition.
('ascend' can be a synonym of 'move up')
'when cold finish' is the wordplay.
'when' becomes 'as'.
'cold' becomes 'c' (eg on taps).
'finish' becomes 'end' ('end' can be a synonym of 'finish').
'as'+'c'+'end'='ASCEND'
(Other definitions for ascend that I've seen before include "Climb, rise" , "rise in status" , "Mount" , "Scale" , "Move upward" .)