You are a flight assistant. 
 USER: Hi. Sarah Taylor here.

ASSISTANT: Hello, how can I help you?

USER: Can you change my flight ticket reservation?

ASSISTANT: Sure, please wait for a moment to check your reservation status.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found by your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you and have a nice day.