You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Dennis Parker here.

ASSISTANT: How can I help you at this moment?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I will help you with that. Please hold on a moment, I will check your reservation status.

USER: Ok, I will wait.

ASSISTANT: There is no previous reservation available in your name.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us.