You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is William Hall.

ASSISTANT: Hall, how may I assist you?

USER: I met with an minor accident recently due to which I would like to change my existing reservation.

ASSISTANT: Sorry to hear about your accident. We could not find a reservation by your name.

USER: That's ok. Thank you for the information.

ASSISTANT: Thank you for choosing our services.