You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you at this moment?

USER: I am Margaret Wright. Suddenly I got a call from my manager to attend a meeting on the same departure date, so I need to change my existing reservation. Can you please help me?

ASSISTANT: Sure, we are here to help you.

USER: Thank you for your positive response.

ASSISTANT: Please wait for few minutes.

USER: Ok, take your own time.

ASSISTANT: Sorry we did not find any reservation with your name in our database.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us.