You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I am Kenneth Thomas from Atlanta. I want to change my travel dates in my previous reservation, can you help me with that?

ASSISTANT: Sure, I will help you with that. Please wait for a minute.

USER: Thank you. Ok.

ASSISTANT: I am sorry to say that there is no reservation found.

USER: Oh! It's ok no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your service.