You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what can I do for you?

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

ASSISTANT: Sure, I am here to help.

USER: Thank you.

ASSISTANT: Please provide me the name on which you have booked the ticket.

USER: Sure, my name is Gary Hall.

ASSISTANT: Please wait while I look into your current reservation.

USER: Sure, I will wait.

ASSISTANT: Gary I am sorry to inform that there is no reservation found on your name.

USER: Ok, that's fine. Thank you for your service.

ASSISTANT: Thank you.