You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you today?

USER: I need to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: I will definitely help you in changing your reservation.

USER: Thank you for considering my request.

ASSISTANT: Please, share me your good name to check your reservation status.

USER: Sure, myself Mark White.

ASSISTANT: Ok, please wait for a while. I will check your reservation status and get back to you.

USER: Sure, I will wait for your response.

ASSISTANT: We regret to inform you that, we have not found any active reservation on your name in our database.

USER: Not an issue, anyway thank you for the information.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your service.