Used another assistant (6,4)
I believe the answer is:
second hand
'used' is the definition.
(I know that used can be written as second-hand)
'another assistant' is the wordplay.
'another' becomes 'second'.
'assistant' becomes 'hand' (hand can mean a worker or employee).
'second'+'hand'='SECOND-HAND'
(Other definitions for second hand that I've seen before include "Pointer on dial" , "going quickly on the clock?" , "Watch component" , "being employed again" , "Part of a timepiece" .)