You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: Can you help me to change my existing reservation on the name of Kimberly Garcia?

ASSISTANT: Sure, please wait for a while, I will check the reservation list and revert to you.

USER: Ok.

ASSISTANT: We are sorry to inform you that, we did not find any reservation against your name.

USER: Ok, no problem. Thank you for informing us.

ASSISTANT: Thank you for reaching us. Have a good day.