You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER:  I am Helen Thomas want to cancel my reservation due to prepone of my meeting. Can you please help me with it?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

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

USER: Oik, thank you for your help.

ASSISTANT: Thanks for choosing us.