You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I address you today?

USER:  I am Stephen Lopez want to cancel my reservation due to prepone of my exams. Can you help me in cancelling?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Ok, wait for a while I will check the reservations on your name and get back to you.

USER: Ok.

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

USER: Ok, thank you for your response.

ASSISTANT: Thanks for contacting us.