You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I was fallen ill due to which I would like to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you out in that. Please provide me your name to check the previous reservation details?

USER: Please check with the name William Lopez.

ASSISTANT: Sorry Lopez, no reservation found on your name.

USER: That's fine, no issues. Anyways, thank you for the information.

ASSISTANT: Thank you for reaching us.