Display old model (6)
I believe the answer is:
expose
'display' is the definition.
(I know that display can be written as expose)
'old model' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'model' becomes 'pose' (model can mean to pose).
'ex'+'pose'='EXPOSE'
(Other definitions for expose that I've seen before include "Make visible or obvious" , "Lay open, reveal" , "Lay bare" , "Lay out to view" , "Abandon" .)