You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Gregory Walker here.

ASSISTANT: Walker, how may I aid you?

USER: Can you cancel my flight ticket reservation?

ASSISTANT: Sure, I will help you. Please wait, let me check your reservation status.

USER: Ok.

ASSISTANT: Walker, I did not find any reservation under your name in our database.

USER: Ok, not a problem. Thank you.

ASSISTANT: You are welcome and thank you for choosing us.