You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Matthew Gonzalez.

ASSISTANT:  How can I aid you?

USER: Owing to an emergency I had to requested for this change reservation. Can you please help me to change an existing reservation?

ASSISTANT: OK, please wait.

USER: Sure.

ASSISTANT: Sorry, no reservation was found on your name.

USER: Ok, not a problem. Thanks for your information.

ASSISTANT:  Thank you for availing us.