You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you at this moment?

USER: I am Timothy Gonzalez. Will you please change my existing reservation as my plan to meet my friend got postponed?

ASSISTANT: Sure, please wait for couple of minutes.

USER: Sure.

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

USER: It's ok, not an issue. Thank you for the information.

ASSISTANT: Thank you for contacting us.