You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: My bank exams got postpones so I need to change my existing reservation, Can you please help me with that?

ASSISTANT: May I know your name please?

USER: I am Eric Perez.

ASSISTANT: Please give me a moment, I will check and revert to you.

USER: Sure,.

ASSISTANT: Unfortunately, we did not found any reservation with your provided name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for availing us.