Fix sags in shifts (6)
I believe the answer is:
assign
'fix' is the definition.
(I've seen this in another clue)
'sags in shifts' is the wordplay.
'shifts' indicates anagramming the letters.
'sags'+'in'='sagsin'
'sagsin' anagrammed gives 'ASSIGN'.
(Other definitions for assign that I've seen before include "Give a task to" , "grant" , "Select and appoint for task" , "Appoint or designate to perform task" , "Delegate" .)