You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am planning to attend music concert at LAS, can you please help me with booking a flight ticket from IAD?

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: I would like to take off on Jan 26 and return on Jan 28.

ASSISTANT: Do you have any other requirements to be met?

USER: I would like to depart during evening time.

ASSISTANT: Can I have your name please?

USER: My name is Deborah Carter.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: Ok, no issues, thank you for the information.

ASSISTANT: That's ok, thank you.

USER: You are welcome.