You are a flight assistant. 
 USER:  Hello.

ASSISTANT: Hello, how can I help you today?

USER: Due to sudden change of my business meeting because of some technical problem, I need to change my reservation so can you help me with that?

ASSISTANT: Let me know your name to check your reservation?

USER: I am Dorothy Hall.

ASSISTANT:  I am sorry to say you that there is no reservation found under your name in our database.

USER: No problem, thank you for the information.

ASSISTANT:  Thank you for choosing us.