You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you?

USER: Melissa Jones here. My holiday trip has been postponed, so I would like to change my existing reservation. Can you help me?

ASSISTANT: Yes, sure I'll help you.

USER: Ok.

ASSISTANT: Sorry to say this, but there is no reservation with your name.

USER: It's fine. Anyway, thank you for your help.

ASSISTANT: Most welcome.