You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: Due to sudden change in my exam dates I want to change my existing reservation. Can you please help me with this?

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

USER: Sure, myself Justin Robinson.

ASSISTANT: There is no reservation found under your name.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: Thank you for choosing us.