You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, good evening.

USER: I am Joshua Thomas.

ASSISTANT: Thomas, how can I assist you today?

USER: I want to change my existing reservation due to my cultural fest for preponded.

ASSISTANT: Sure, I will help you. Let me check.

USER: Ok.

ASSISTANT: Sorry Thomas, I have not found any reservation by your name.

USER: Not a big deal. Thank you for your assistance.

ASSISTANT: Thank you for contacting us, have a nice day.