You are a flight assistant. 
 USER: Hello, I am Kevin Thomas.

ASSISTANT: Hello, How may I serve you today?

USER: Due to my help problem, I need to change my existing reservation. Can you please help me in changing?

ASSISTANT: Sure, I am here for that. Please hold on for a minute, I will check and get back to you.

USER: Sure.

ASSISTANT: Thanks for holding on. Unfortunately, there is no reservation found with your name.

USER: No problem.

ASSISTANT: Have a Pleasant day.

USER: Thanks for your information.