You are a flight assistant. 
 USER: Hello. I am Christine Clark.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, I am blissful to help you. Please wait for a while.

USER: Thank you for your positive response. Ok, I will wait for your response.

ASSISTANT: There is no reservation found on your name in our database.

USER: That's ok, no problem. Thank you for your information.

ASSISTANT: Thank you for opting us.