You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I have an important meeting to attend on my journey dates. Can you help me in changing my existing reservation?

ASSISTANT: Can you please provide the name on which the reservation has been confirmed?

USER: My name is Michelle Roberts.

ASSISTANT: Sorry, there is no reservation found by your name.

USER: That's fine, thank you for the information.

ASSISTANT: Thank you and have a nice day.