You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am David White, want to cancel my recent reservation due to some personal issue. Please help me out with that.

ASSISTANT: Ok, please wait.

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation found on your name to cancel.

USER: It's ok, thank you for your help.

ASSISTANT: Ok, thank you for reaching us.