Engineers point to prompt delivery (6)
I believe the answer is:
rescue
'delivery' is the definition.
('rescue' can be a synonym of 'delivery')
'engineers point to prompt' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'point' becomes 's' (S is an example).
'to prompt' becomes 'cue' ('cue' can be a synonym of 'prompt').
're'+'s'+'cue'='RESCUE'
(Other definitions for rescue that I've seen before include "Save - deliver" , "Free someone from trouble" , "Deliver from danger" , "gets one out of a tight corner" , "Get over, on top of" .)