You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Can you please help me in changing my existing reservation, as my exam got postponed.

ASSISTANT: Sure, may I know your good name please?

USER: I am Donald Wright.

ASSISTANT: Ok, please wait for few minutes.

USER: Ok.

ASSISTANT: There is no existing reservation found on your name in our data base.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.