You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Myself David Taylor from New York. I want to change my travel dates in my previous reservation. Can you please help me with that?

ASSISTANT: Sure, take your time. Sorry to say, there is no reservation on  your name in our database.

USER: Oh! It's ok no problem.

ASSISTANT: Thank you for your help.

USER: Thank you for your information.