1- Listen to the Guest carefully without interruption (you can only take a notes while the Guest is talking)
2- Ever Never let the Guest fell that you are against what he is saying otherwise the Guest will forget the Problem and you will become his Problem.
3- Start your talking with the Guest thankfully saying (thank you for bringing this Issue to our attention).
4- Be smart enough and handle only the Problem that you are able to handle otherwise refer to your Supervisor or your Manager.
5- Report the Complaint to the Management even if you handled or you didn't.
6- Don't refer direct to the General Manager because if he interfered he will give a big compensation.
7- Follow up with the Guest or the responsible Department for the Complaint that everything is ok.