You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I abet you?

USER: I am Charles Carter. I need to change my existing reservation as my source airport has been changed. Will you help me in Changing my reservation?

ASSISTANT: Sure. Please wait fora  while, I will check your reservation.

USER: Sure.

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

USER: Ok, no issues. Thank you for quick response.

ASSISTANT: Thank you for approaching us.