You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am David Thompson. Due to some problems my trip was cancelled so can you please cancel my flight ticket?

ASSISTANT: Yes, I am here to assist you. Please be online for a while, let me check your reservation status in our database.

USER: Ok, thank you for your response.

ASSISTANT: Sorry, I have not found any reservation under your name in our database.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: You are most welcome and thank you for contacting us.