You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Brenda Edwards here. Due to my health issues I would like to change my recent reservation which I have done last week to Denver. Can you help me to change my existing reservation?

ASSISTANT: Sure, I am happy to help you.

USER: Ok.

ASSISTANT: Please wait for a while, I will check and get back you.

USER: Ok, please.

ASSISTANT: We did not found any reservation on your given name.

USER: Its ok, thank you for the information.

ASSISTANT: Thanks for choosing us.