You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How exactly I can serve you the best today?

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

ASSISTANT: Let me know your name to check your reservation?

USER: I am Michelle Roberts.

ASSISTANT: Sorry, we found no reservation on your given name.

USER:  No problem, thanks for the information.

ASSISTANT: Thank you for choosing us.