Hi, this is John, I’m not available to take your call, but please leave your name, number and a brief message. I’ll get back to you as soon as possible.
你好，我是John。我现在不能接你的电话，但是请留下你的名字，电话号码和简短的留言，我会尽快给你回电话的，

John, it’s Susan and I really need to talk to you, I won’t be able to go to the party with you，please call me at 3244548 when you get back.
Joh，我是Susan，我真的需要和你通话，我不能和你去参加派对了，请回来后给我回电话3244548。