You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you please help me?

ASSISTANT: Sure, may I know your name please?

USER: I am Emily Johnson.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: That's ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us.