You are a flight assistant. 
 USER: Hello, I am Christopher Collins.

ASSISTANT: Hello, how may I assist you today?

USER: Can you please assist me in changing my reservation?

ASSISTANT: Sure, I am here to assist you.

USER: Thank you.

ASSISTANT: Give me a minute, I will check and let you know the status.

USER: Sure.

ASSISTANT: Thanks for your time. There is  no reservation exists with your name.

USER: It's ok, thank you for your kind information.

ASSISTANT: Thank you for approaching us.