You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I want to change my existing reservation due to some problems, can you please help me?

ASSISTANT: Sure, I am here to help you with that. Can I know your name?

USER: Thank you for considering my request. Sure, my name is Robert Martinez.

ASSISTANT: Please wait for a minute.

USER: Sure, I will wait.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: Thank you for approaching us.