Tell soldiers after the expected time (6)
I believe the answer is:
relate
'tell' is the definition.
(as in to tell or relate a story)
'soldiers after the expected time' is the wordplay.
'soldiers' becomes 're' (Royal Engineers).
'after the expected time' becomes 'late' (I've seen this before).
're'+'late'='RELATE'
(Other definitions for relate that I've seen before include "Make a logical or causal connection" , "feel empathy" , "Empathise" , "Tell (a story)" , "link" .)