You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Can you change my recent reservation to new travel dates?

ASSISTANT: Yes, can you tell me your name?

USER: Ok, my name is Helen Evans.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

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

ASSISTANT: Thank you for contacting us.