Standard part of working is negotiating to get promoted (6)
I believe the answer is:
ensign
'standard' is the definition.
(both can mean a flag)
'part of working is negotiating to get promoted' is the wordplay.
'part of' indicates a hidden word.
'to get promoted' says the letters should be written backwards (in a down clue, letters get sent up).
'ngisne' can be found hidden inside 'working is negotiating'.
'ngisne' reversed gives 'ENSIGN'.
(Other definitions for ensign that I've seen before include "National flag" , "officer in the US navy" , "In British infantry, a colours bearer" , "Standard - flag" , "Soldier; standard" .)