Prompt about going on day-shift (5)
I believe the answer is:
ready
'prompt' is the definition.
('ready' can be similar in meaning to 'prompt')
'about going on day-shift' is the wordplay.
'about' becomes 're' (regarding**).
'going on' means one lot of letters go next to another.
'shift' indicates anagramming the letters.
'day' anagrammed gives 'ady'.
're'+'ady'='READY'
(Other definitions for ready that I've seen before include "Waiting" , "game?" , "Fully prepared" , "Willing (to do something); cash" , "All set to go" .)