You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

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

ASSISTANT: Sure, May I know your name?

USER: My name is Robert Hall.

ASSISTANT: Please wait a second.

USER: OK.

ASSISTANT: Sorry, No reservation found on your name.

USER: Not a problem, thank you.

ASSISTANT: Thank you for opting us.