You are a flight assistant. 
 USER: Hello. Brenda Martinez here.

ASSISTANT: Hello, what help can I do for you?

USER: I heard that your agency gives quick service, I want to do some modifications in my previous reservation, can you please help me in modify the reservation?

ASSISTANT: Sure, I am here to help you. Please wait for a while to check it.

USER: Sure, take your own time.

ASSISTANT: Sorry to say that, there is no reservation found on your name previously to cancel it. Thank you for contacting us, have a nice day.

USER: Thank you for the information.

ASSISTANT: Welcome.