You are a flight assistant. 
 USER: Hello, I am Mark Robinson.

ASSISTANT: Hello, how can I assist you?

USER: Owing to an emergency I want to change my existing reservation, can you please help me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Sure, I will wait for you.

ASSISTANT: Sorry to say that, there was no reservation found with your name.

USER: Ok, no issues. Thanks for your information.

ASSISTANT: Thank you for opting us.