You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How best I can aid you today?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, may I know your name please?

USER: Sure, Margaret Hall here.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our records.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.