Hope you are using JTAPI\TAPI application and i think if the call is active there is no chance to receive the events, Next time i would request you to post your query under IP Phone Services.
Please refer this url - Waiting call Which seems to be a similar issue that you are looking for.
Thanks and Regards,
I've moved the discussion to IP Phone Services forum. If using CiscoIPPhoneExecute, you can set the priority so that the message gets displayed on the phone after the call ends.
For the most reliable results, as mentioned the CTI APIs (TAPI/JTAPI) will allow applications to be notified via event in real-time of the call status of a phone.
Somewhat less reliable but potentially easier to implement: I've seen some applications query the /StreamingStatisticsX page (available from the phone's on-board web server) to identify whether it looks like the device has an active call stream. See the IPPS apps dev notes doc for details on this URL.