Plan to uplift US soldiers in retreat (6)
I believe the answer is:
design
'plan' is the definition.
(design is a kind of plan)
'uplift us soldiers in retreat' is the wordplay.
'uplift' says the letters should be written backwards.
'us soldiers' becomes 'gis' (GI, nickname for US soldier).
'in' means one lot of letters goes inside another.
'retreat' becomes 'den'.
'gis' reversed gives 'sig'.
'sig' placed into 'den' is 'DESIGN'.
'to' acts as a link.
(Other definitions for design that I've seen before include "Develop a drawing or model" , "Aim -- decorative pattern" , "Develop or prepare a plan" , "Devise, dreate, make out a plan" , "Preliminary sketch or plan" .)