Work, function (7)
I believe the answer is:
operate
I believe this clue is a double definition.
'work' is the first definition.
(I know that work can be written as operate)
'function' is the second definition.
(I know that function can be written as operate)
(Other definitions for operate that I've seen before include "Control, run, a mcahine say" , "Manage, run" , "Work, function" , "Perform surgery or run a machine" , "(Of machine) function" .)