You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I guide you now?

USER: I want to change my existing reservation which is done recently due to some problems, can you please help me in this?

ASSISTANT: Sure, I am gleeful to help you with that. Can you please provide your name to check your previous reservation?

USER: Thank you. Sure, my name is Jeffrey Lee.

ASSISTANT: Please be on hold to check.

USER: Sure, I will wait.

ASSISTANT: We regret to inform you that, there is no reservation found on your name in our records.

USER: Ok, not an issue. Anyways, thank you for your service.

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