Soldiers having to deal with retirement (7)
I believe the answer is:
retreat
'retirement' is the definition.
('retreat' can be a synonym of 'retirement')
'soldiers having to deal' is the wordplay.
'soldiers' becomes 're' (Royal Engineers).
'having' is a charade indicator (letters next to each other).
'to deal' becomes 'treat' (I've seen this before**).
're'+'treat'='RETREAT'
'with' acts as a link.
(Other definitions for retreat that I've seen before include "snug" , "What cowards might do" , "Take flight" , "place for meditation" , "Give ground" .)