By default, Extension 700 is used to park calls. While in a conversation, press '#' to initiate a transfer, then dial '700' (e.g. '#700'). You will hear a voice telling you the extension at which the call was parked (most likely '701' or '702'). Now hang up. The caller will be left on hold at the announced extension. On a different phone, dial the announced extension (e.g. '701'), and call the parked party