You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, please wait for moment.

USER: Thank you. Ok.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: No issue.

ASSISTANT: Thank you for choosing us.

USER: Thank you.