You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what can I guide you at this moment?

USER: I am Thomas Parker. Can you please help me to change my reservation?

ASSISTANT: Yes, I will help you about it. Give me a moment to check the existing reservation.

USER: Sure.

ASSISTANT: Sorry Parker, there is no reservation under your name in our listings.

USER: That is fine. Thank you for your help.

ASSISTANT: Thank you for opting our service. Hope you have a gleeful day.