Recover one's possession? (6)
I believe the answer is:
'recover' is the definition.
(I know that recover can be written as regain)
'one's possession?' is the wordplay.
'one' becomes 're' (I am not sure about this - if you are sure you should believe this answer much more).
'possession?' becomes 'gain' (gain is a kind of possession).
Can you help me to learn more?
(Other definitions for regain that I've seen before include "Recover, retrieve" , "Win back" , "Get back, recover the use of" , "Recover - in gear (anag)" , "Possess once more for regina" .)