我有一个返回对象的Soap WS

[DataContract(Namespace = Configuration.Namespace)]
  public class GetAccountResponse
  {  [DataMember]
    public List<Account> accounts { get; set; }
   }
  [DataContract(Namespace = Configuration.Namespace)]
   public class Account
  { [DataMember(Name = "GUIDAccount")]
      public Guid? accountid { get; set; }
    [DataMember]
      public List<Contract> Contracts { get; set; }
   }
     [DataContract(Namespace = Configuration.Namespace)]
       public struct Contract
        {
        [DataMember(Name = "IDContrat")]
         public string contrat { get; set; }

         [DataMember(Name = "Phone")]
          public string phone { get; set; }
  }

我需要向协定添加一个新属性，但仅限于特定的请求条件。

[DataMember(Name = "state")]
          public string state { get; set; }

回应：

//all the time
    return new GetAccountResponse
                    {
                        accounts = myaccounts.Values.ToList()
                    };
                    
   //my request matches a critertia the obejcts with the new 
      attribute

       if(//mycriteria)

       return new GetAccountResponse //object with state attribute
                    {
                        accounts = myaccounts.Values.ToList()
                    };

如何通过使用相同的GetAccountResponse对象来实现这一点？