You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How could I assist you today?

USER: I am David Nelson. I want to cancel my recent reservation due to heavy rainfall, can you help me in cancel reservation?

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Unfortunately there is no reservation found with your given name in our data.

USER: No problem, thank you for your help.

ASSISTANT: Thank you for choosing us.