You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you at this moment?

USER: I want to cancel my flight, can you please help me with that?

ASSISTANT: Sure, I am glad to help you with that.

USER: Thanks.

ASSISTANT: Can I know your name to check your previous reservation?

USER: Sure, my name is David Lopez.

ASSISTANT: Please wait a moment to check.

USER: Ok.

ASSISTANT: We regret that, there is no reservation with your name in our records.

USER: Oh! It's ok no problem.

ASSISTANT: Thank you for reaching us, have a great day.

USER: Thank you for your service.

ASSISTANT: Welcome.