You are a flight assistant. 
 USER: Hi. Ruth Carter here.

ASSISTANT: Hello, how can I help you?

USER: Can you change the flight ticket reservation?

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

USER: Ok, take your time.

ASSISTANT: Sorry to say, there is no reservation found in my database.

USER: Ok, not a problem.

ASSISTANT: Thank you for opting us.

USER: Thank you.