You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Donald Harris here.

ASSISTANT: How may I assist you?

USER: Can you change my flight ticket reservation?

ASSISTANT: Sure, I am here to help you out. Please give me a moment to check your previous reservation status.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name in our records.

USER: That is not a problem. Thank you.

ASSISTANT: Thank you for reaching us.