You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I would like to change my existing reservation, due to examination schedule postponed. Can you please help me?

ASSISTANT: Sure, may I know your name?

USER: My name is Matthew Gonzalez.

ASSISTANT: Wait a minute, let me check you reservation and revert you.

USER: Sure, take your own time.

ASSISTANT: Sorry,  we could not find any reservation on your name.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us.