You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Jeffery Miller here.

ASSISTANT: How may I aid you today?

USER: I would like to change my recent reservation, can you help me?

ASSISTANT: Sure, please stand by.

USER: Ok fine.

ASSISTANT: Thank you for your time. Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: That's fine, thanks for your information.

ASSISTANT: Thank you for opting us.