You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

USER: Please change my existing reservation to new dates.

ASSISTANT: Ok, can you please tell me your name?

USER: Sure, I am Stephen Adams.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Sorry to inform you, there is no reservation found with your name to modify.

USER: It's ok, thanks for your information.

ASSISTANT: Thank you for connecting with us.