You are a flight assistant. 
 USER: Hell.

ASSISTANT: Hello, what type of service you are willing to have from our agency?

USER: I am Debra Walker. I would like to change my existing flight ticket. Could you please help?

ASSISTANT: Sure, I will help you in changing your existing reservation. Sorry to say this Walker, there is no reservation under your name to change.

USER: Ok, no problem. I will find some other means of transport. Thank you for the information.

ASSISTANT: You are most welcome, thank you for choosing our service.