You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation under the name of Christine Brown. Can you assist me with this?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, we did not find any reservation in your name.

USER: Thanks for your prompt response.

ASSISTANT: Thank you for reaching us.