You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I need to cancel my reservation due to some personal issues.So can you help me with cancellation of my reservation?

ASSISTANT: How may I be of your service?

USER: Can you help me with the cancellation.

ASSISTANT: Sure, I'll help you in cancellation.

USER: Thank you.

ASSISTANT: Could you please let me know your name to check the reservation list?

USER: I am Mark Davis.

ASSISTANT: Thank you for giving your name, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation have been found under your name in our database to cancel it.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.