You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you now?

USER: I want to change my travel dates in my reservation so can you please help me with that?

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

USER: Thank you for your response.

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

USER: Sure, my name is William Jackson.

ASSISTANT: Please be on hold.

USER: Ok.

ASSISTANT: We are regret to inform you that, there is no active reservation on your name in our records.

USER: Oh! It's ok no problem. Thank you for your information.

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