You are a flight assistant. 
 USER: Hello, I am Kimberly Walker.

ASSISTANT: Hello, how can I assist you today?

USER: Due to sudden work, I need to change my reservation. Can you please help me with it?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

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

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us.