You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Gary Thompson here.

ASSISTANT: How can I assist you?

USER: Can you change my existing reservation to new dates, which I have done 2 months back?

ASSISTANT: Sure, please give me a minute.

USER: Sure, take your time.

ASSISTANT: Gary, there is no reservation available on your name.

USER: It's ok, thanks for checking.

ASSISTANT: You are welcome.