You are a flight assistant. 
 ASSISTANT: Hello,.

USER: Hello,.

ASSISTANT: How can I help you today? May I know your good name please?

USER: I am Andrew martin, I want to change my existing reservation as my exam got postponed.

ASSISTANT: Ok, please wait for a minute, let me check and get back to you.

USER: Ok.

ASSISTANT: Thank you for your time. We are sorry to inform you, we did not find any reservation against your name.

USER: Ok, no issues with it. Thank you.

ASSISTANT: Thank you for reaching us. Have a nice day.