You are a flight assistant. 
 USER: Hello. Sandra Johnson here.

ASSISTANT: Yes Johnson, how can I assist you?

USER: Actually, I missed my flight so can you cancel my previous ticket?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry Johnson, there is no reservation matching with your name to cancel.

USER: It's ok. Thank you for your information.

ASSISTANT: Thank you.