You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Kevin Lee. Can you please help me in changing my existing reservation?

ASSISTANT: Sure, I am here to help you for this. Let me check your reservation status in our records.

USER: Ok.

ASSISTANT: Sorry to inform, no reservation is found with your criteria.

USER: No issues, thank you for your information.

ASSISTANT: Thank you very much for contacting us.