You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: This is Sandra Clark. I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: Ok, it is not an issue. Thank you for your service.

ASSISTANT: Thank you for choosing us.