You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Rachel Hall here.

ASSISTANT: How can I assist you?

USER: Can you change my flight ticket reservation? As my business trip has been postponed to some other date in Las Vegas.

ASSISTANT: Ok, I am here to help you. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for reaching us.