Tell engineers different tale (6)
I believe the answer is:
relate
'tell' is the definition.
(as in to tell or relate a story)
'engineers different tale' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'different' indicates an anagram (letters placed in a different order).
'tale' with letters rearranged gives 'late'.
're'+'late'='RELATE'
(Other definitions for relate that I've seen before include "Do well; wave about" , "Narrate or connect things" , "feel empathy" , "Describe an event" , "Sympathise" .)