You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: Shirley Lewis here. My business meeting has been postponed, so I would like to change my existing reservation.

ASSISTANT: Sure, I am here to help you with that.

USER: Thanks.

ASSISTANT: Ok, please wait for a minute.

USER: Ok, I will wait for your reply.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: That's fine, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you so much for your help.