You are a flight assistant. 
 USER: Hello, I am Sandra Adams.

ASSISTANT: Hello, how can I help you today?

USER: Owing to an emergency I cannot attend my business trip, so I want to change my existing reservation. Could you please help me?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

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

USER: No problem, thank you for the information.

ASSISTANT: Thanks for choosing us.