Assign a position to, at headquarters (7)
I believe the answer is:
station
I believe this clue is a triple definition!
'assign' is the first definition.
(thesaurus)
'a position' is the second definition.
(station is a kind of position)
'to' is a link.
'at headquarters' is the third definition.
'station' can be an answer for 'headquarters' (I've seen this before). I am not certain of the 'at' bit.
Can you help me to learn more?
(Other definitions for station that I've seen before include "HQ - stopping place - post" , "Broadcasting channel" , "Base, post" , "Place - railway stop - HQ - standing" , "TV or radio channel" .)