You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I need to change my reservation due to my exams got postponed so please help me with changing my reservation.

ASSISTANT: Ok, can you please share your name with me?

USER: Sure, please check the reservation with the name of Helen Thomas.

ASSISTANT: Please wait for a while.

USER: Sure, take your time.

ASSISTANT: Helen Thomas, I have to inform you about it but no reservation was found by your name.

USER: It's ok fine, no problem.

ASSISTANT: Thank you for reaching us.

USER: Anyway, thank you for your time.

ASSISTANT: Have a nice day.