You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: My name is William Martinez. My holiday trip has been postponed, so I would like to change my existing reservation.

ASSISTANT: Ok. I will help you, please give me a moment.

USER: Ok.

ASSISTANT: There is no reservation on your name. Sorry for inconvenience.

USER: That's fine, thank you for your help.

ASSISTANT: Thank you for reaching us.