Allow users to “park” a phone call with a parking extension number, placing it on hold to be answered on a softphone or any other phone in the office. The caller is put on hold while users switch phones.
You are taking an important business call and you can not make such vital decision. You want to transfer this call to your manager but he is busy talking to someone else. So you ask the caller to wait and park this call. The caller will be on hold and you manager can pick this call up the moment he is available.