AMI Atxfer function problem

I have a problem with the AMI Atxfer function, according to my test, this function just works when the person is callee (the person who recieve the call) and when I call someone and I use this function, I can just hear some dial tones, but nothing happens.

So does anyone know how to fix it or it is what this function can do?

asterisk version: 1.8.7.0 and 1.8.20.0

Thanks.