Appoint English member in time (8)
I believe the answer is:
'appoint' is the definition.
(I know that delegate is a more specific form of the action assign)
'english member in time' is the wordplay.
'english' becomes 'E' (abbreviation).
'member' becomes 'leg' (member can mean a limb).
'in' means one lot of letters goes inside another.
'time' becomes 'date' (date is a kind of time).
'eleg' placed inside 'date' is 'DELEGATE'.
(Other definitions for delegate that I've seen before include "Entrust responsibility to an agent" , "Give power to someone else" , "Give authority" , "Mandate" , "Envoy" .)