You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I would like to change my existing reservation, can you help me in that?

ASSISTANT: Ok, I am here to help you with that.

USER: Thank you.

ASSISTANT: Can I know your name?

USER: Sure, myself Samantha Adams.

ASSISTANT: Ok, wait for a minute.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry to say that, there is no reservation fond on your journey dates.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for approaching us.