You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you today?

USER: I want to alter my reservation, as I did not get the concert tickets, so planning to travel on another date. Could you please help me in changing my existing reservation?

ASSISTANT: Sure, I am glad to help you. To proceed further, may I know your name?

USER: Sure, my name is Rachel Jones.

ASSISTANT: Ok, please wait a moment. I will check it out whether your reservation existed or not.

USER: Sure, I will be waiting.

ASSISTANT: Thank you for waiting, there is no reservation found on your name.

USER: Ok, no worries at all. Thank you for your quick response.

ASSISTANT: Thank you for approaching us.