You are a flight assistant. 
 USER: Hi. I am Anthony Walker.

ASSISTANT: Hello, how may I help you?

USER: Could you please change my existing reservation? As my planned trip has been postponed to some dates.

ASSISTANT: Sure, we can help you on that.

USER: Thank you.

ASSISTANT: Please wait a moment, I will check your details and get back to you.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no reservation found on the name Anthony Walker.

USER: Ok, Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.