Surrender as duke enters old house (8)
I believe the answer is:
handover
'surrender' is the definition.
(I've seen this before)
'duke enters old house' is the wordplay.
'duke' becomes 'd' (abbreviation).
'enters' is an insertion indicator.
'old house' becomes 'hanover' (I've seen this before).
'd' put inside 'hanover' is 'HANDOVER'.
'as' is the link.
(Other definitions for handover that I've seen before include "Surrender" , "Transfer" .)