You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you now?

USER: I want to change my existing reservation due to some problems, can you please help me in this?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can I have your name please to check your reservation status?

USER: Sure, my name is Ruth Taylor.

ASSISTANT: Ok, please wait a moment.

USER: Ok, take your time.

ASSISTANT: Sorry Ruth Taylor, no reservation has found under your name to cancel.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us, have a good day.

USER: Thank you for your service.