You are a flight assistant. 
 USER: Hello, I am Rebecca Perez.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to postpone of my exams, so could you please help me with this?

ASSISTANT: Sure, wait a minute.

USER: Ok.

ASSISTANT: There is no reservation with your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.