You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, please help me with your name.

USER: Sure, myself Joseph Walker.

ASSISTANT: Thank you information, please be online.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, we did not find any reservation by your name in our database.

USER: That's ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for the information.