You are a flight assistant. 
 USER: Hello, my name is George Martin.

ASSISTANT: Hello, how may I help you today?

USER: I would like to book a ticket from NY-EWR to TX-DFW, can you please help me to book a ticket? I would like to leave between 01/30 and 02/01.

ASSISTANT: Sure, I am glad to help you. Please give me a minute I will check and come back to you.

USER: Ok, I will wait.

ASSISTANT: Thank you for waiting, we are sorry to say we did not find any flight with your requirements.

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

ASSISTANT: Thank you for choosing us, have a nice day.