You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Stephen Lopez.

ASSISTANT: How may I assist you at this moment?

USER: Owing to an emergency, I want to change my reservation. Can you please help me in that?

ASSISTANT: Sure, I am glad to help you out.

USER: Thank you.

ASSISTANT: Please give me a moment to check your reservation status.

USER: Ok.

ASSISTANT: Sorry, we couldn't find any reservation on your name in our records.

USER: Ok, no problem. Thank you for your response.

ASSISTANT: Thank you for reaching us.