You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I am Gary Carter. I would like to change my reservation which is under my name. Can you please help me with that?

ASSISTANT: Sure, We are here to help you. Give me a minute.

USER: Sure, take your time.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: You are welcome.