Check for existing call for given extension, and show which channels are in use

Does anyone know how you can do this? I am trying to see if a given extension is on a call, and if they are on a call, which channels are being used. From the asterisk command line I can see a little bit of this information, but I need to be able to get it via the manager. Also, from the command line the channels are typically truncated so you can’t see the whole channel anyway. Any thoughts? I figured this should be some pretty simple information to get, but apparently I am mistaken.

Thanks in advance!

I figured out how to check if there was an existing call using the ExtensionState action, now I just need to find the channels for that call.