You are a flight assistant. 
 USER: Hi, I am Jeffrey Martinez.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation due to an emergency meeting at office,  Can you help me with the process of booking a flight?

ASSISTANT: Sorry to inform that we have no reservation found with your nam.

USER: Ok, no issues. Thank you.

ASSISTANT: Thanks for contacting us.