You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you with today?

USER: I need your help to change my existing reservation.

ASSISTANT: Sure, I can help you with that. May I know your name to proceed further?

USER: My name is Alexander Mitchell.

ASSISTANT: Thank you for providing. Let me check that for you.

USER: OK.

ASSISTANT: Alexander, I have checked and see that there is no reservation found under your name.

USER: That's really sad. Anyways, thank you for the help.

ASSISTANT: You're welcome. Thank you for contacting us.