You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sandra Mitchell.

ASSISTANT: How can I serve you?

USER: Can you please help me to cancel my reservation?

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: There is no reservation found with your given name.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.