How to re-establish connection between end users in UCMA?

Question

After remote user closed his Lync chat window, the state of conversation is Terminated. how can i re-establish them?

what is wrong with my doing?( it throws "The operation is invalid in the current object state (Terminated)")

void conversation_StateChanged(object sender, StateChangedEventArgs<ConversationState> e)
    {
        if (e.State == ConversationState.Terminated)
        {
            _terminated = true;
        }
        if (e.State == ConversationState.Established)
        {
            _terminated = false;
        }
    }
if (_terminated)
            {
                imCall.BeginEstablish(null, null, (ar) =>
                {
                    flow = imCall.Flow;
                    _callEstablishComplete.Set();
                }, null);
                _callEstablishComplete.WaitOne();
            }

Answer 1

through dozens times of trials, i found it is very easy to solve. what i should do is to create a new IM call object:

conversation = new Conversation(endPoint, settings);
imCall = new InstantMessagingCall(conversation);
imCall.BeginEstablish("sip:xxx@abc.com", null, (ar) =>
            {
                    imCall.EndEstablish(ar);
                    flow = imCall.Flow;
                    _callEstablishComplete.Set();
            }, null);

that is enough!