You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Kimberly Thompson here. I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, please wait for a while.

USER: Thank you for considering my request. Sure, I will wait for your response.

ASSISTANT: Sorry to say that, there was no reservation found with your given name.

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

ASSISTANT: Thank you for choosing us.