If the guest who comes in the hotel is very angry and does not want to Atvahm and you are asked to return his money because the service is good, what are the appropriate ways in this case?

i will try to calm him down maybe bring him something to drink and then listen to his complaints carefully and patiently and more importantly convince him to stay and reward him with the best care and service and never forget to keep my smiley face no matter how angry and agressive the custemor was