You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you?

USER: I am Rachel Lewis. Can you help me in changing my previous reservation?

ASSISTANT: Sure, please give me a moment to check your details.

USER: Sure.

ASSISTANT: Rachel Lewis, there is no reservation found under your name to change.

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

ASSISTANT: Thank you for contacting our service.