You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I address you?

USER: I am Andrew Green. As there is a change in trip, I would like to change my existing reservation. Will you help me in this?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will get back to you with current status.

USER: Sure.

ASSISTANT: Thanks for waiting but I am sorry to inform that there is no reservation found with your name.

USER: Ok, thanks for the quick response.

ASSISTANT: Thanks for reaching us.