You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Due to sudden change in my trip to another location, I would like to do some changes in existing my reservation. Can you please help me out?

ASSISTANT: Sure, I am happy to help you. May I know your good name?

USER: Donna Lewis here.

ASSISTANT: Sorry, there is no active reservation on your name in our records.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.