You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Ashley Walker. Actually, I want to change an existing reservation.Can you help me out?

ASSISTANT: Sure, wait for a minute.

USER: Sure.

ASSISTANT: Sorry, Ashley no reservation found on your name.

USER: That's fine.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your help.