You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Brain Hernandez.

ASSISTANT: How can I aid you?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure. Wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, There is no reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your information.