You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How shall I assist you?

USER: I am Rachel Phillips. Can you help me to change my recent reservation, so I can re-plan my journey?

ASSISTANT: Please wait for a while.

USER: Yes, I will wait for you.

ASSISTANT: No reservation is available.

USER: That's ok, thank you for helping me.

ASSISTANT: Thank you.