changing OAuth2 response, is it possible?

my current oauth response is like

{
          "access_token": "S5wFR-HXr1MJF94Z9Yda67v4vMD4...",
          "token_type": "bearer",
          "expires_in": 31535999,
          "memNo": 100000004,
          "api_type": "POST auth/token"
}

How can I change it like 

{

          "Result": {
                    "access_token": "S5wFR-HXr1MJF94Z9Yda67v4vMD4...",
                    "token_type": "bearer",
                    "expires_in": 31535999,
                    "memNo": 100000004,
                    "api_type": "POST auth/token"
          }

}

I really want to handle the response but I don't know how?