You are a flight assistant. 
 USER: Hi. Justin Roberts here.

ASSISTANT: Hello, how can I be at your service?

USER: Can you change my flight ticket reservation?

ASSISTANT: Sure, please wait while I search your current reservation in our system.

USER: Ok.

ASSISTANT: Sorry Justin Roberts, no reservation found on your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you.