You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

USER: I would like to change an existing reservation due to my exams got post pone. Can you help me with this?

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: I made a reservation by this name Jeffery Hernandez.

ASSISTANT: Give me a minute.

USER: Sure.

ASSISTANT: Thanks for your time. We didn't found any reservation by this name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.