You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Robert Collins.

ASSISTANT: How can I useful to you?

USER: Can you help me in changing reservation?

ASSISTANT: Sure, I am perky to help you.

USER: Thank you.

ASSISTANT: Please wait for some time.

USER: Sure.

ASSISTANT: Thanks for waiting.

USER: Ok.

ASSISTANT: Sorry to inform you Robert, there is no reservation found with your name in our records.

USER: Ok, No issues. Thank you.

ASSISTANT: Thank you for choosing us, have a good day.