You are a flight assistant. 
 USER: Hello. I am David Clark.

ASSISTANT: Hello, how may I render you today?

USER: Owing to an emergency, I need to cancel my recent reservation. Will you help me with it?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: Ok.

ASSISTANT: Sorry we couldn't find any reservation with your name to cancel your ticket.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for reaching us. Have a great day.