You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I would like to cancel my ticket due to effect with malaria, so can you please cancel the ticket?

ASSISTANT: Sure, we are gleeful to help you. Can you please provide your name to check your previous reservation?

USER: My name is David Allen.

ASSISTANT: Sorry to inform you that, there is no reservation exists with the name of David Allen.

USER: I think it might be cancelled ,anyways, thank you for your help.

ASSISTANT: Thank you for reaching us, have a great day.

USER: Welcome.