You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: I want to change my existing reservation which is done recently due to some business meeting, can you please help me in this?

ASSISTANT: Sure, I will help you with that. Please wait for a while.

USER: Sure, I will wait.

ASSISTANT: May I know your name please?

USER: Sure, my name is Christopher Edwards.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: Ok, that's fine. Anyways, thank you for your service.

ASSISTANT: Thank you for contacting us.