You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Due to an emergency, I want to change my existing reservation, can you help me with that?

ASSISTANT: Sure, may I know your name please?

USER: I am Catherine Mitchell.

ASSISTANT: Ok, please wait for a moment, I will check and get back to you.

USER: OK.

ASSISTANT: Thanks for waiting. Sorry, no reservation found with your name.

USER: Ok, Thanks for your response.

ASSISTANT: Thank you for choosing us.